+1, Thanx folks for your efforts on this! I didn't have time to review everything thoroughly, but my initial pass suggests it looks good or atleast is safe to merge. If I find some spare time, I'll test it further and submit a ticket or so if I encounter any issues.
Good Luck!!! -Ayush On Tue, 31 Dec 2024 at 16:39, Hui Fei <feihui.u...@gmail.com> wrote: > > Thanks Zander for bringing this discussion again and trying your best to push > it forward. It's really a long time since last discussion. > > It’s indeed time, +1 for merging phase 1 codes based on the following points > - The phase 1 feature has been running at scale within companies for a long > time > - The long-term plan is clear, and also addressed some questions raised by > the community > - The testing result of future features on memory and performance > > ZanderXu <zande...@apache.org> 于2024年12月31日周二 15:36写道： >> >> Hi, everyone: >> >> Time to Merge FGL Phase I >> >> The PR for FGL Phase I is ready for merging! Please take a moment to review >> and cast your vote: https://github.com/apache/hadoop/pull/6762. >> >> The FGL Phase I has been running successfully in production for over six >> months at Shopee and BOSS Zhipin, with no reported performance or stability >> issues. It’s now the right time to merge it into the trunk branch, allowing >> us to move forward with Phase II. >> >> The global lock remains the default lock mode, but users can enable FGL by >> configuring >> dfs.namenode.lock.model.provider.class=org.apache.hadoop.hdfs.server.namenode.fgl.FineGrainedFSNamesystemLock. >> >> If there are no objections within 7 days, I will propose an official vote. >> >> Performance and Memory Usage of Phase I >> >> Conclusion： >> >> Fine-grained locks do not lead to significant performance improvements. >> >> Fine-grained locks do not result in additional memory consumption >> >> Reasons: >> >> BM operations heavily depend on FS operations: IBR and BR still acquire the >> global lock (FSLock and BMLock). >> >> FS operations depend on BM operations: Common operations (create, addBlock, >> getBlockLocations) also acquire the global lock (FSLock and BMLock). >> >> Phase II will bring significant performance improvements by decoupling FS >> and BM dependencies and replacing the global FSLock with a fine-grained >> IIPLock. >> >> Addressing Common Questions >> >> Thank you all for raising meaningful questions! >> >> I have rewritten the design document to improve clarity. >> https://docs.google.com/document/d/1DXkiVxef9wCmICjpZyIQO-yxsgwc4wnf2lTKQ3UXe30/edit?usp=sharing >> >> Below is a summary of frequently asked questions and answers: >> >> Summary of Questions: >> >> Question 1: How is the performance of LockPoolManager? >> >> Performance Report: >> >> Time to acquire a cached lock: 194 ns >> >> Time to acquire a non-cached lock: 1044 ns >> >> Time to release an in-use lock: 88 ns >> >> Time to release an unused lock: 112 ns >> >> Overall Performance: >> >> QPS: Over 10 million >> >> Time to acquire the IIP lock for a path with depth 10: >> >> Fully uncached: 10440 ns + 1120 ns (≈ 11 μs) >> >> Fully cached: 1940 ns + 1120 ns (≈ 3 μs) >> >> In global lock scenarios, lock wait times are typically in the millisecond >> range. Therefor, the cost of acquiring and releasing fine-grained locks can >> be ignored. >> >> Question 2: How much memory does the FGL consume? >> >> Memory Consumption: >> >> A single LockResource contains a read-write lock and a counter, totaling >> approximately 200 bytes: >> >> LockResource: 24 bytes >> >> ReentrantReadWriteLock: 150 bytes >> >> AtomicInteger: 16 bytes >> >> Memory Usage Estimates: >> >> 10-level directory depth, 100 handlers >> >> 1000 lock resources, approximately 200 KB >> >> 10-level directory depth, 1000 handlers >> >> 10000 lock resources, approximately 2 MB >> >> 1, 000,000 lock resources, approximately 200 MB >> >> Conclusion: Memory consumption is negligible. >> >> Question 3: What happens if no lock is available in the LockPoolManager? >> >> If there are not any available LockResources, two solutions are available: >> >> Return a RetryException, prompting the client to retry later. >> >> Temporarily increase the lock entity limit, allocate more locks to meet >> client requests, and use an asynchronous thread to recycle locks >> periodically. >> >> We can provide multiple LockPoolManager implementations for users to choose >> from based on production environments. >> >> Question 4: Regarding the IIPLock lock depth issue, can we consider holding >> only the first 3 or 4 levels of directory locks? >> >> This approach is not recommended for the following reasons: >> >> Cannot maximize concurrency. >> >> Limited savings in lock acquisition/release time and memory usage, yielding >> insignificant benefits. >> >> Question 5: How should attributes like StoragePolicy, ErasureCoding, and >> ACL, which can be set on parent or ancestor directory nodes, be handled? >> >> ErasureCoding and ACL: >> >> When changing node attributes, hold the corresponding INode’s write lock. >> >> When using ancestor node attributes, hold the corresponding INode’s read >> lock. >> >> StoragePolicy: >> >> More complex due to its impact on both directory tree operations and Block >> operations. >> >> To improve performance, commonly used block-related operations (such as >> BR/IBR) should not acquire IIPLock >> >> Detailed design documentation: >> https://docs.google.com/document/d/1DXkiVxef9wCmICjpZyIQO-yxsgwc4wnf2lTKQ3UXe30/edit?tab=t.0#heading=h.96lztsl4mwfk >> >> Question 6: How should FGL be implemented for the SNAPSHOT feature? >> >> Since the Rename operation on the SNAPSHOT directory is supported, holding >> only the write lock of the SNAPSHOT root directory cannot cover the rename >> situation, so the thread safety of SNAPSHOT-related operations cannot be >> guaranteed >> >> It is recommended to use global FS lock to ensure thread safety. >> >> Detailed design documentation: >> https://docs.google.com/document/d/1DXkiVxef9wCmICjpZyIQO-yxsgwc4wnf2lTKQ3UXe30/edit?tab=t.0#heading=h.sm36p6bfcpec >> >> Question 7: How should FGL be implemented for the Symlinks feature? >> >> The Target path of Symlinks is a string, and the client performs a second >> forward access to the Target path. So the fine-grained lock project requires >> no special handling >> >> For the createSymlink RPC, the FGL needs to acquire the IIPLocks for both >> target and link paths. >> >> Question 8: How should FGL be implemented for the reserved feature? >> >> The Reserved feature has two usage modes: >> >> /.reserved/iNodes/${inode id} >> >> /.reserved/raw/${path} >> >> INodeId Mode: During the resolvePath phase, obtain the real IIPLock lock via >> INodeId. >> >> Path Mode: During the resolvePath phase, obtain the real IIPLock lock via >> path. >> >> Detailed design documentation: >> https://docs.google.com/document/d/1DXkiVxef9wCmICjpZyIQO-yxsgwc4wnf2lTKQ3UXe30/edit?tab=t.0#heading=h.h6rcpzkbpanf >> >> Question 9: Why is INodeFileLock used as the FGL for BlockInfo? >> >> INodeFile and Block have mutual dependencies: >> >> INodeFile depends on Block for state and size. >> >> Block depends on INodeFile for state and storage policy. >> >> Therefore, using INodeFileLock as the fine-grained lock for BlockInfo is a >> reasonable choice. >> >> Detailed design documentation: >> https://docs.google.com/document/d/1DXkiVxef9wCmICjpZyIQO-yxsgwc4wnf2lTKQ3UXe30/edit?tab=t.0#heading=h.zesd6omuu3kr >> >> Seeking Community Feedback >> >> Your questions and concerns are always welcome. >> >> We can discuss them in detail on the Slack Channel: >> https://app.slack.com/client/T4S1WH2J3/C06UDTBQ2SH >> >> Let’s work together to advance the Fine-Grained Lock project. I believe this >> initiative will deliver significant performance improvements to the HDFS >> community and help reinvigorate its activity. >> >> Wishing everyone a Happy New Year 2025! >> >> >> On Wed, 5 Jun 2024 at 16:17, ZanderXu <zande...@apache.org> wrote: >>> >>> I plan to hold a meeting on 2024-06-06 from 3:00 PM - 4:00 PM to share the >>> FGL's motivations and some concerns in detail in Chinese. >>> >>> The doc is : NameNode Fine-Grained Locking Based On Directory Tree (II) >>> >>> The meeting URL is: https://sea.zoom.us/j/94168001269 >>> >>> You are welcome to this meeting. >>> >>> On Mon, 6 May 2024 at 23:57, Hui Fei <feihui.u...@gmail.com> wrote: >>>> >>>> BTW, there is a Slack channel hdfs-fgl for this feature. can join it and >>>> discuss more details. >>>> >>>> Is it necessary to hold a meeting to discuss this? So that we can push it >>>> forward quickly. Agreed with ZanderXu, it seems inefficient to discuss >>>> details via email list. >>>> >>>> >>>> Hui Fei <feihui.u...@gmail.com> 于2024年5月6日周一 23:50写道： >>>>> >>>>> Thanks all >>>>> >>>>> Seems all concerns are related to the stage 2. We can address these and >>>>> make it more clear before we start it. >>>>> >>>>> From development experience, I think it is reasonable to split the big >>>>> feature into several stages. And stage 1 is also independent and it also >>>>> can be as a minor feature that uses fs and bm locks instead of the global >>>>> lock. >>>>> >>>>> >>>>> ZanderXu <zande...@apache.org> 于2024年4月29日周一 15:17写道： >>>>>> >>>>>> Thanks @Ayush Saxena <ayush...@gmail.com> and @Xiaoqiao He >>>>>> <hexiaoq...@apache.org> for your nice questions. >>>>>> >>>>>> Let me summarize your concerns and corresponding solutions: >>>>>> >>>>>> *1. Questions about the Snapshot feature* >>>>>> It's difficult to apply the FGL to Snapshot feature, but we can just >>>>>> using >>>>>> the global FS write lock to make it thread safe. >>>>>> So if we can identity if a path contains the snapshot feature, we can >>>>>> just >>>>>> using the global FS write lock to protect it. >>>>>> >>>>>> You can refer to HDFS-17479 >>>>>> <https://issues.apache.org/jira/browse/HDFS-17479> to get how to identify >>>>>> it. >>>>>> >>>>>> Regarding performance of the operations related to the snapshot features, >>>>>> we can discuss it in two categories: >>>>>> Read operations involves snapshots: >>>>>> The FGL branch uses the global write lock to protect them, the GLOBAL >>>>>> branch uses the global read lock to protect them. It's hard to conclude >>>>>> which version has better performance, it depends on the global lock >>>>>> competition. >>>>>> >>>>>> Write operations involves snapshots: >>>>>> Both FGL and GLOBAL branch use the global write lock to protect them. >>>>>> It's >>>>>> hard to conclude which version has better performance, it depends on the >>>>>> global lock competition too. >>>>>> >>>>>> So I think if namenode load is low, the GLOBAL branch will have a better >>>>>> performance than FGL; If namenode load is high, the FGL branch may have a >>>>>> better performance than the GLOBAL, which also depends on the ratio of >>>>>> read >>>>>> and write operations on the SNAPSHOT feature. >>>>>> >>>>>> We can do somethings to let end-user to choose a branch with a better >>>>>> branch according to their business: >>>>>> First, we need to make the lock mode can be selectable, so that end-user >>>>>> can choose to use FGL of GLOBAL. >>>>>> Second, using the global write lock to make operations related to >>>>>> snapshot >>>>>> thread safe as I described in HDFS-17479. >>>>>> >>>>>> >>>>>> *2. Questions about the Symlinks feature* >>>>>> If Symlink is related to snapshot, we can refer to the solution of the >>>>>> snapshot; If Symlink is not related to snapshot, I think it's easy to >>>>>> meet >>>>>> the FGL. >>>>>> Only createSymlink involves two paths, FGL just need to lock them in the >>>>>> order to make this operation thread. For other operations, it is the same >>>>>> as other normal iNode, right? >>>>>> >>>>>> If I missed difficult points, please let me know. >>>>>> >>>>>> >>>>>> *3. Questions about Memory Usage of iNode locks* >>>>>> I think there are too many solutions to limit the memory usage of these >>>>>> iNode locks, such as: Using a limit capacity lock pool to ensure the >>>>>> maximum memory usage, Just holding iNode locks for fixed depth of >>>>>> directories, etc. >>>>>> >>>>>> We can just abstract this LockManager first and then support its >>>>>> implementation with different ideas, so that we can limit the maximum >>>>>> memory usage of these iNode locks. >>>>>> FGL can acquire or lease iNode locks through LockManager. >>>>>> >>>>>> >>>>>> *4. Questions about Performance of acquiring and releasing iNode locks* >>>>>> We can add some benchmark for LockManager, to test the performance or >>>>>> acquire and release unblocked locks. >>>>>> >>>>>> >>>>>> *5. Questions about StoragePolicy, ECPolicy, ACL, Quota, etc.* >>>>>> These policies may be sot on an ancestor node and used by some children >>>>>> files. The set operation for these policies will be protected by the >>>>>> directory tree, since there are all file-related operations. In addition >>>>>> to Quota and StoragePolicy, the use of other policies will also be >>>>>> protected by directory tree, such as ECPolicy and ACL. >>>>>> >>>>>> Quota is a little special since its update operations may not be >>>>>> protected >>>>>> by the directory tree, we can assign a locks to each QuotaFeature and use >>>>>> these locks to make updating operations thread safe. you can refer to >>>>>> HDFS-17473 <https://issues.apache.org/jira/browse/HDFS-17473> to get some >>>>>> detailed information. >>>>>> >>>>>> StoragePolicy is a little special since it is used not only by >>>>>> file-related >>>>>> operations but also block-related operations. >>>>>> ProcessExtraRedundancyBlock >>>>>> uses storage policy to choose redundancy replicas and >>>>>> BlockReconstructionWork uses storage policy to choose target DNs. In >>>>>> order >>>>>> to maximize the performance improvement, BR and IBR should only involve >>>>>> the >>>>>> iNodeFile to which the current processing block belongs. These redundancy >>>>>> blocks can be processed by the Redundancy monitor while holding the >>>>>> directory tree locks. You can refer to HDFS-17505 >>>>>> <https://issues.apache.org/jira/browse/HDFS-17505> to get more detailed >>>>>> informations. >>>>>> >>>>>> *6. Performance of the phase 1* >>>>>> HDFS-17506 <https://issues.apache.org/jira/browse/HDFS-17506> is used to >>>>>> do >>>>>> some performance testing for phase 1, and I will complete it later. >>>>>> >>>>>> >>>>>> Discuss solution through mails is not efficient, you can create one >>>>>> sub-tasks under HDFS-17366 >>>>>> <https://issues.apache.org/jira/browse/HDFS-17366> to describe your >>>>>> concerns and I will try to give some answers. >>>>>> >>>>>> Thanks @Ayush Saxena <ayush...@gmail.com> and @Xiaoqiao He >>>>>> <hexiaoq...@apache.org> again. >>>>>> >>>>>> >>>>>> >>>>>> On Mon, 29 Apr 2024 at 02:00, Ayush Saxena <ayush...@gmail.com> wrote: >>>>>> >>>>>> > Thanx Everyone for chasing this, Great to see some momentum around FGL, >>>>>> > that should be a great improvement. >>>>>> > >>>>>> > I have some two broad categories: >>>>>> > ** About the process:* >>>>>> > I think in the above mails, there are mentions that phase one is >>>>>> > complete >>>>>> > in a feature branch & we are gonna merge that to trunk. If I am >>>>>> > catching it >>>>>> > right, then you can't hit the merge button like that. To merge a >>>>>> > feature >>>>>> > branch. You need to call for a Vote specific to that branch & it >>>>>> > requires 3 >>>>>> > binding votes to merge, unlike any other code change which requires 1. >>>>>> > It >>>>>> > is there in our Bylaws. >>>>>> > >>>>>> > So, do follow the process. >>>>>> > >>>>>> > ** About the feature itself:* (A very quick look at the doc and the >>>>>> > Jira, >>>>>> > so please take it with a grain of salt) >>>>>> > * The Google Drive link that you folks shared as part of the first >>>>>> > mail. I >>>>>> > don't have access to that. So, please open up the permissions for that >>>>>> > doc >>>>>> > or share the new link >>>>>> > * Chasing the design doc present on the Jira >>>>>> > * I think we only have Phase-1 ready, so can you share some metrics >>>>>> > just >>>>>> > for that? Perf improvements just with splitting the FS & BM Locks >>>>>> > * The memory implications of Phase-1? I don't think there should be any >>>>>> > major impact on the memory in case of just phase-1 >>>>>> > * Regarding the snapshot stuff, you mentioned taking lock on the root >>>>>> > itself? Does just taking lock on the snapshot root rather than the FS >>>>>> > root >>>>>> > works? >>>>>> > * Secondly about the usage of Snapshot or Symlinks, I don't think we >>>>>> > should operate under the assumptions that they aren't widely used or >>>>>> > not, >>>>>> > we might just not know folks who don't use it widely or they are just >>>>>> > users >>>>>> > not the ones contributing. We can just accept for now, that in those >>>>>> > cases >>>>>> > it isn't optimised and we just lock the entire FS space, which it does >>>>>> > even >>>>>> > today, so no regressions there. >>>>>> > * Regarding memory usage: Do you have some numbers on how much the >>>>>> > memory >>>>>> > footprint increases? >>>>>> > * Under the Lock Pool: I think you are assuming there would be very few >>>>>> > inodes where lock would be required at any given time, so there won't >>>>>> > be >>>>>> > too much heap consumption? I think you are compromising on the >>>>>> > Horizontal >>>>>> > Scalability here. I doubt if your assumption doesn't hold true, under >>>>>> > heavy >>>>>> > read load by concurrent clients accessing different inodes, the >>>>>> > Namenode >>>>>> > will start giving memory troubles, that would do more harm than good. >>>>>> > Anyway Namenode heap is way bigger problem than anything, so we should >>>>>> > be >>>>>> > very careful increasing load over there. >>>>>> > * For the Locks on the inodes: Do you plan to have locs for each inode? >>>>>> > Can we somehow limit that to the depth of the tree? Like currently we >>>>>> > take >>>>>> > lock on the root, have a config which makes us take lock at Level-2 or >>>>>> > 3 >>>>>> > (configurable), that might fetch some perf benefits and can be used to >>>>>> > control the memory usage as well? >>>>>> > * What is the cost of creating these inode locks? If the lock isn't >>>>>> > already cached it would incur some cost? Do you have some numbers >>>>>> > around >>>>>> > that? Say I disable caching altogether & then let a test load run, what >>>>>> > does the perf numbers look like in that case >>>>>> > * I think we need to limit the size of INodeLockPool, we can't let it >>>>>> > grow >>>>>> > infinitely in case of heavy loads and we need to have some auto >>>>>> > throttling mechanism for it >>>>>> > * I didn't catch your Storage Policy problem. If I decode it right, the >>>>>> > problem is like the policy could be set on an ancestor node & the >>>>>> > children >>>>>> > abide by that & this is the problem, if that is the case then isn't >>>>>> > that >>>>>> > the case with ErasureCoding policies or even ACLs or so? Can you >>>>>> > elaborate >>>>>> > a bit on that. >>>>>> > >>>>>> > >>>>>> > Anyway, regarding the Phase-1. If you share (the perf numbers with >>>>>> > proper >>>>>> > details + Impact on memory if any) for just phase 1 & if they are good, >>>>>> > then if you call for a branch merge vote for Phase-1 FGL, you have my >>>>>> > vote, >>>>>> > however you'll need to sway the rest of the folks on your own :-) >>>>>> > >>>>>> > Good Luck, Nice Work Guys!!! >>>>>> > >>>>>> > -Ayush >>>>>> > >>>>>> > >>>>>> > On Sun, 28 Apr 2024 at 18:32, Xiaoqiao He <hexiaoq...@apache.org> >>>>>> > wrote: >>>>>> > >>>>>> >> Thanks ZanderXu and Hui Fei for your work on this feature. It will be >>>>>> >> a very helpful improvement for the HDFS module in the next journal. >>>>>> >> >>>>>> >> 1. If we need any more review bandwidth, I would like to be involved >>>>>> >> to help review if possible. >>>>>> >> 2. From the design document there are still missing some detailed >>>>>> >> descriptions such as snapshot, symbolic link and reserved etc as >>>>>> >> mentioned >>>>>> >> above. I think it will be helpful for newbies who want to be involved >>>>>> >> if all corner >>>>>> >> cases are considered and described. >>>>>> >> 3. From slack, we plan to check into the trunk at this phase. I am not >>>>>> >> sure >>>>>> >> If it is the proper time, following the dev plan there are two steps >>>>>> >> left >>>>>> >> to >>>>>> >> finish this feature from the design document, right? If that, I think >>>>>> >> we >>>>>> >> should >>>>>> >> postpone checking in when all plans are ready. Considering that there >>>>>> >> are >>>>>> >> many unfinished tries for this feature in history, I think postpone >>>>>> >> checking >>>>>> >> will be the safe way, another way it will involve more rebase cost if >>>>>> >> you >>>>>> >> keep >>>>>> >> separate dev branch, however I think It is not one difficult thing for >>>>>> >> you. >>>>>> >> >>>>>> >> Good luck and look forward to making that happen soon! >>>>>> >> >>>>>> >> Best Regards, >>>>>> >> - He Xiaoqiao >>>>>> >> >>>>>> >> On Fri, Apr 26, 2024 at 3:50 PM Hui Fei <feihui.u...@gmail.com> wrote: >>>>>> >> > >>>>>> >> > Thanks for interest and advice on this. >>>>>> >> > >>>>>> >> > Just would like to share some info here >>>>>> >> > >>>>>> >> > ZanderXu leads this feature and he has spent a lot of time on it. >>>>>> >> > He is >>>>>> >> the main developer in stage 1. Yuanboliu and Kokonguyen191 also took >>>>>> >> some >>>>>> >> tasks. Other developers (slfan1989 haiyang1987 huangzhaobo99 >>>>>> >> RocMarshal >>>>>> >> kokonguyen191) helped review PRs. (Forgive me if I missed someone) >>>>>> >> > >>>>>> >> > Actually haiyang1987, Yuanboliu and Kokonguyen191 are also very >>>>>> >> familiar with this feature. We discussed many details offline. >>>>>> >> > >>>>>> >> > Welcome to more people interested in joining the development and >>>>>> >> > review >>>>>> >> of the stage 2 and 3. >>>>>> >> > >>>>>> >> > >>>>>> >> > Zengqiang XU <xuzengqiang5...@gmail.com> 于2024年4月26日周五 14:56写道： >>>>>> >> >> >>>>>> >> >> Thanks Shilun for your response: >>>>>> >> >> >>>>>> >> >> 1. This is a big and very useful feature, so it really needs more >>>>>> >> >> developers to get on board. >>>>>> >> >> 2. This fine grained lock has been implemented based on internal >>>>>> >> branches >>>>>> >> >> and has gained benefits by many companies, such as: Meituan, >>>>>> >> >> Kuaishou, >>>>>> >> >> Bytedance, etc. But it has not been contributed to the community >>>>>> >> >> due >>>>>> >> to >>>>>> >> >> various reasons, such as there is a big difference between the >>>>>> >> >> version >>>>>> >> of >>>>>> >> >> the internal branch and the community trunk branch, the internal >>>>>> >> branch may >>>>>> >> >> ignore some functions to make FGL clear, and the contribution >>>>>> >> >> needs a >>>>>> >> lot >>>>>> >> >> of work and will take many times. It means that this solution has >>>>>> >> already >>>>>> >> >> been practiced in their prod environment. We have also practiced >>>>>> >> >> it in >>>>>> >> our >>>>>> >> >> prod environment and gained benefits, and we are also willing to >>>>>> >> >> spend >>>>>> >> a >>>>>> >> >> lot of time contributing to the community. >>>>>> >> >> 3. Regarding the benchmark testing, we don't need to pay more >>>>>> >> attention to >>>>>> >> >> whether the performance is improved by 5 times, 10 times or 20 >>>>>> >> >> times, >>>>>> >> >> because there are too many factors that affect it. >>>>>> >> >> 4. As I described above, this solution is already being practiced >>>>>> >> >> by >>>>>> >> many >>>>>> >> >> companies. Right now, we just need to think about how to implement >>>>>> >> >> it >>>>>> >> with >>>>>> >> >> high quality and more comprehensively. >>>>>> >> >> 5. I firmly believe that all problems can be solved as long as the >>>>>> >> overall >>>>>> >> >> solution is right. >>>>>> >> >> 6. I can spend a lot of time leading the promotion of this entire >>>>>> >> feature >>>>>> >> >> and I hope more people can join us in promoting it. >>>>>> >> >> 7. You are always welcome to raise your concerns. >>>>>> >> >> >>>>>> >> >> >>>>>> >> >> Thanks Shilun again, I hope you can help review designs and PRs. >>>>>> >> >> Thanks >>>>>> >> >> >>>>>> >> >> On Fri, 26 Apr 2024 at 08:00, slfan1989 <slfan1...@apache.org> >>>>>> >> >> wrote: >>>>>> >> >> >>>>>> >> >> > Thank you for your hard work! This is a very meaningful >>>>>> >> >> > improvement, >>>>>> >> and >>>>>> >> >> > from the design document, we can see a significant increase in >>>>>> >> >> > HDFS >>>>>> >> >> > read/write throughput. >>>>>> >> >> > >>>>>> >> >> > I am happy to see the progress made on HDFS-17384. >>>>>> >> >> > >>>>>> >> >> > However, I still have some concerns, which roughly involve the >>>>>> >> following >>>>>> >> >> > aspects: >>>>>> >> >> > >>>>>> >> >> > 1. While ZanderXu and Hui Fei have deep expertise in HDFS and are >>>>>> >> familiar >>>>>> >> >> > with related development details, we still need more community >>>>>> >> member to >>>>>> >> >> > review the code to ensure that the relevant upgrades meet >>>>>> >> expectations. >>>>>> >> >> > >>>>>> >> >> > 2. We need more details on benchmarks to ensure that test results >>>>>> >> can be >>>>>> >> >> > reproduced and to allow more community member to participate in >>>>>> >> >> > the >>>>>> >> testing >>>>>> >> >> > process. >>>>>> >> >> > >>>>>> >> >> > Looking forward to everything going smoothly in the future. >>>>>> >> >> > >>>>>> >> >> > Best Regards, >>>>>> >> >> > - Shilun Fan. >>>>>> >> >> > >>>>>> >> >> > On Wed, Apr 24, 2024 at 3:51 PM Xiaoqiao He >>>>>> >> >> > <hexiaoq...@apache.org> >>>>>> >> wrote: >>>>>> >> >> > >>>>>> >> >> >> cc private@h.a.o. >>>>>> >> >> >> >>>>>> >> >> >> On Wed, Apr 24, 2024 at 3:35 PM ZanderXu <zande...@apache.org> >>>>>> >> wrote: >>>>>> >> >> >> > >>>>>> >> >> >> > Here are some summaries about the first phase: >>>>>> >> >> >> > 1. There are no big changes in this phase >>>>>> >> >> >> > 2. This phase just uses FS lock and BM lock to replace the >>>>>> >> original >>>>>> >> >> >> global >>>>>> >> >> >> > lock >>>>>> >> >> >> > 3. It's useful to improve the performance, since some >>>>>> >> >> >> > operations >>>>>> >> just >>>>>> >> >> >> need >>>>>> >> >> >> > to hold FS lock or BM lock instead of the global lock >>>>>> >> >> >> > 4. This feature is turned off by default, you can enable it by >>>>>> >> setting >>>>>> >> >> >> > dfs.namenode.lock.model.provider.class to >>>>>> >> >> >> > >>>>>> >> org.apache.hadoop.hdfs.server.namenode.fgl.FineGrainedFSNamesystemLock >>>>>> >> >> >> > 5. This phase is very import for the ongoing development of >>>>>> >> >> >> > the >>>>>> >> entire >>>>>> >> >> >> FGL >>>>>> >> >> >> > >>>>>> >> >> >> > Here I would like to express my special thanks to >>>>>> >> >> >> > @kokonguyen191 >>>>>> >> and >>>>>> >> >> >> > @yuanboliu for their contributions. And you are also welcome >>>>>> >> >> >> > to >>>>>> >> join us >>>>>> >> >> >> > and complete it together. >>>>>> >> >> >> > >>>>>> >> >> >> > >>>>>> >> >> >> > On Wed, 24 Apr 2024 at 14:54, ZanderXu <zande...@apache.org> >>>>>> >> wrote: >>>>>> >> >> >> > >>>>>> >> >> >> > > Hi everyone >>>>>> >> >> >> > > >>>>>> >> >> >> > > All subtasks of the first phase of the FGL have been >>>>>> >> >> >> > > completed >>>>>> >> and I >>>>>> >> >> >> plan >>>>>> >> >> >> > > to merge them into the trunk and start the second phase >>>>>> >> >> >> > > based >>>>>> >> on the >>>>>> >> >> >> trunk. >>>>>> >> >> >> > > >>>>>> >> >> >> > > Here is the PR that used to merge the first phases into >>>>>> >> >> >> > > trunk: >>>>>> >> >> >> > > https://github.com/apache/hadoop/pull/6762 >>>>>> >> >> >> > > Here is the ticket: >>>>>> >> https://issues.apache.org/jira/browse/HDFS-17384 >>>>>> >> >> >> > > >>>>>> >> >> >> > > I hope you can help to review this PR when you are available >>>>>> >> and give >>>>>> >> >> >> some >>>>>> >> >> >> > > ideas. >>>>>> >> >> >> > > >>>>>> >> >> >> > > >>>>>> >> >> >> > > HDFS-17385 >>>>>> >> >> >> > > <https://issues.apache.org/jira/browse/HDFS-17385> >>>>>> >> is >>>>>> >> >> >> used for >>>>>> >> >> >> > > the second phase and I have created some subtasks to >>>>>> >> >> >> > > describe >>>>>> >> >> >> solutions for >>>>>> >> >> >> > > some problems, such as: snapshot, getListing, quota. >>>>>> >> >> >> > > You are welcome to join us to complete it together. >>>>>> >> >> >> > > >>>>>> >> >> >> > > >>>>>> >> >> >> > > ---------- Forwarded message --------- >>>>>> >> >> >> > > From: Zengqiang XU <zande...@apache.org> >>>>>> >> >> >> > > Date: Fri, 2 Feb 2024 at 11:07 >>>>>> >> >> >> > > Subject: Discussion about NameNode Fine-grained locking >>>>>> >> >> >> > > To: <hdfs-dev@hadoop.apache.org> >>>>>> >> >> >> > > Cc: Zengqiang XU <xuzengqiang5...@gmail.com> >>>>>> >> >> >> > > >>>>>> >> >> >> > > >>>>>> >> >> >> > > Hi everyone >>>>>> >> >> >> > > >>>>>> >> >> >> > > I have started a discussion about NameNode Fine-grained >>>>>> >> >> >> > > Locking >>>>>> >> to >>>>>> >> >> >> improve >>>>>> >> >> >> > > performance of write operations in NameNode. >>>>>> >> >> >> > > >>>>>> >> >> >> > > I started this discussion again for serval main reasons: >>>>>> >> >> >> > > 1. We have implemented it and gained nearly 7x performance >>>>>> >> >> >> improvement in >>>>>> >> >> >> > > our prod environment >>>>>> >> >> >> > > 2. Many other companies made similar improvements based on >>>>>> >> >> >> > > their >>>>>> >> >> >> internal >>>>>> >> >> >> > > branch. >>>>>> >> >> >> > > 3. This topic has been discussed for a long time, but still >>>>>> >> without >>>>>> >> >> >> any >>>>>> >> >> >> > > results. >>>>>> >> >> >> > > >>>>>> >> >> >> > > I hope we can push this important improvement in the >>>>>> >> >> >> > > community >>>>>> >> so >>>>>> >> >> >> that all >>>>>> >> >> >> > > end-users can enjoy this significant improvement. >>>>>> >> >> >> > > >>>>>> >> >> >> > > I'd really appreciate you can join in and work with me to >>>>>> >> >> >> > > push >>>>>> >> this >>>>>> >> >> >> > > feature forward. >>>>>> >> >> >> > > >>>>>> >> >> >> > > Thanks very much. >>>>>> >> >> >> > > >>>>>> >> >> >> > > Ticket: HDFS-17366 < >>>>>> >> https://issues.apache.org/jira/browse/HDFS-17366> >>>>>> >> >> >> > > Design: NameNode Fine-grained locking based on directory >>>>>> >> >> >> > > tree >>>>>> >> >> >> > > < >>>>>> >> >> >> >>>>>> >> https://docs.google.com/document/d/1X499gHxT0WSU1fj8uo4RuF3GqKxWkWXznXx4tspTBLY/edit?usp=sharing >>>>>> >> >> >> > >>>>>> >> >> >> > > >>>>>> >> >> >> >>>>>> >> >> >> >>>>>> >> --------------------------------------------------------------------- >>>>>> >> >> >> To unsubscribe, e-mail: private-unsubscr...@hadoop.apache.org >>>>>> >> >> >> For additional commands, e-mail: private-h...@hadoop.apache.org >>>>>> >> >> >> >>>>>> >> >> >> >>>>>> >> >>>>>> >> --------------------------------------------------------------------- >>>>>> >> To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org >>>>>> >> For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org >>>>>> >> >>>>>> >> --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-dev-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-dev-h...@hadoop.apache.org
