= focal verification =
ubuntu@client:~$ cat /proc/version_signature
Ubuntu 5.4.0-102.115-generic 5.4.174
ubuntu@client:~$ ./elbencho/bin/elbencho -t 40 -r -n 10 -N 5000 -s 128k -b 128k
/mnt/nfs/ubuntu
OPERATION RESULT TYPE FIRST DONE LAST DONE
========= ================ ========== =========
READ Elapsed ms : 470642 471169
Files/s : 4245 4244
Throughput MiB/s : 530 530
Total files : 1998154 2000000
Total MiB : 249770 250000
---
ubuntu@client:~$
Regression:
ubuntu@client:~/nfstest$ PYTHONPATH=$(pwd) ./test/nfstest_delegation --client
192.168.42.1 --server 192.168.42.2 -e /srv/nfstest --trcdelay 4
UID is: 1000
Creating: /mnt/t/nfstest_delegation_20220225_223841_f_001
UID is: 1000
Creating: /mnt/t/nfstest_delegation_20220225_223841_f_002
*** Basic READ delegation test
TEST: Running test 'basic01'
PASS: Open file for READ should succeed
PASS: Read file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: READ delegation should be granted
TIME: 5.113318s
*** Basic WRITE delegation test
TEST: Running test 'basic02'
PASS: Open file for WRITE should succeed
PASS: Write file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for WRITE on same process should succeed
PASS: Write file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: Open file for WRITE from a different process should succeed
PASS: Write file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: WRITE delegation should be granted
TIME: 4.940012s
*** Basic READ delegation test with file stat
TEST: Running test 'basic03'
PASS: Stat file to cache file metadata should succeed
PASS: Open file for READ should succeed
PASS: Read file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: LOOKUP operation should be sent
PASS: OPEN should be sent
PASS: OPEN should be sent with CLAIM_FH
PASS: OPEN should be sent with the filehandle of the file to be opened
PASS: READ delegation should be granted
PASS: OPEN should not be sent for the same file
PASS: READs should be sent to the server with the DELEG stateid
PASS: READs should return NFS4_OK from the server
PASS: READ should not be sent when reading delegated file from a different
process
PASS: CLOSE should be sent to the server
PASS: CLOSE should be sent with correct OPEN stateid
PASS: DELEGRETURN should be sent after the close
PASS: DELEGRETURN should be sent with the delegation stateid
TIME: 4.757017s
*** Basic WRITE delegation test with file stat
TEST: Running test 'basic04'
UID is: 1000
Creating: /mnt/t/nfstest_delegation_20220225_223841_f_004
PASS: Stat file to cache file metadata should succeed
PASS: Open file for WRITE should succeed
PASS: Write file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for WRITE on same process should succeed
PASS: Write file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: Open file for WRITE from a different process should succeed
PASS: Write file from a different process should succeed
PASS: LOOKUP operation should be sent
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_FH
FAIL: OPEN should be sent with the filehandle of the file to be opened
FAIL: WRITE delegation should be granted
TIME: 5.090116s
*** Basic READ delegation test with file lock
TEST: Running test 'basic05'
PASS: Open file for READ should succeed
PASS: Lock file with F_RDLCK should succeed
PASS: Read file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
PASS: READ delegation should be granted
PASS: OPEN should not be sent for the same file
PASS: LOCK should not be sent to the server
PASS: READs should be sent to the server with the DELEG stateid
PASS: READs should return NFS4_OK from the server
PASS: READ should not be sent when reading delegated file from a different
process
PASS: CLOSE should be sent to the server
PASS: CLOSE should be sent with correct OPEN stateid
PASS: DELEGRETURN should be sent after the close
PASS: DELEGRETURN should be sent with the delegation stateid
TIME: 4.794486s
*** Basic WRITE delegation test with file lock
TEST: Running test 'basic06'
PASS: Open file for WRITE should succeed
PASS: Lock file with F_WRLCK should succeed
PASS: Write file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for WRITE on same process should succeed
PASS: Write file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: Open file for WRITE from a different process should succeed
PASS: Write file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: WRITE delegation should be granted
TIME: 4.962986s
*** Basic WRITE delegation test using RDWR open while reading
TEST: Running test 'basic07'
PASS: Open file for RDWR should succeed
PASS: Read file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: WRITE delegation should be granted
TIME: 4.806131s
*** Basic WRITE delegation test using RDWR open while writing
TEST: Running test 'basic08'
PASS: Open file for RDWR should succeed
PASS: Write file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: WRITE delegation should be granted
TIME: 4.711963s
*** Basic WRITE delegation test using RDWR open while reading with file stat
TEST: Running test 'basic09'
PASS: Stat file to cache file metadata should succeed
PASS: Open file for RDWR should succeed
PASS: Read file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: LOOKUP operation should be sent
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_FH
FAIL: OPEN should be sent with the filehandle of the file to be opened
FAIL: WRITE delegation should be granted
TIME: 4.749760s
*** Basic WRITE delegation test using RDWR open while writing with file stat
TEST: Running test 'basic10'
UID is: 1000
Creating: /mnt/t/nfstest_delegation_20220225_223841_f_007
PASS: Stat file to cache file metadata should succeed
PASS: Open file for RDWR should succeed
PASS: Write file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
PASS: LOOKUP operation should be sent
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_FH
FAIL: OPEN should be sent with the filehandle of the file to be opened
FAIL: WRITE delegation should be granted
TIME: 4.869004s
*** Basic WRITE delegation test using RDWR open while reading with file lock
TEST: Running test 'basic11'
PASS: Open file for RDWR should succeed
PASS: Lock file with F_RDLCK should succeed
PASS: Read file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: WRITE delegation should be granted
TIME: 4.766863s
*** Basic WRITE delegation test using RDWR open while writing with file lock
TEST: Running test 'basic12'
PASS: Open file for RDWR should succeed
PASS: Lock file with F_WRLCK should succeed
PASS: Write file should succeed
PASS: Open file for READ on same process should succeed
PASS: Read file on same process should succeed
PASS: Open file for READ from a different process should succeed
PASS: Read file from a different process should succeed
FAIL: OPEN should be sent
PASS: OPEN should be sent with CLAIM_NULL
PASS: OPEN should be sent with the name of the file to be opened
PASS: OPEN should be sent with the filehandle of the directory
FAIL: WRITE delegation should be granted
TIME: 4.725836s
169 tests (146 passed, 23 failed)
Total time: 58.446193s
ubuntu@client:~/nfstest$
** Tags removed: verification-needed-focal
** Tags added: verification-done-focal
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Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1957986
Title:
Recalled NFSv4 files delegations overwhelm server
Status in linux package in Ubuntu:
Fix Released
Status in linux source package in Focal:
Fix Committed
Status in linux source package in Hirsute:
Fix Released
Status in linux source package in Impish:
Fix Released
Status in linux source package in Jammy:
Fix Released
Bug description:
[Impact]
An NFSv4 client that does a lot of opens/closes can overwhelm and NFSv4
server, causing a significant drop in performance. In my testing, I've seen
performance drop from ~700MiB/s down to < 10MiB/s. The same workload using
NFSv3 does not have this problem.
[Test Case]
This can be demonstrated using the elbencho benchmark from
https://github.com/breuner/elbencho:
$ elbencho -t 40 -r -n 10 -N 5000 -s 128k -b 128k /mnt/nfs/ubuntu
You'll notice the nfsd threads (I stuck w/ the default of 4) start to
consume 100% CPU, and the performance of the elbencho benchmark will
begin to trickle.
[Fix]
The following fix solves the problem, but there are a number of patches
dependencies required before it will apply to focal:
commit 10717f45639f6c1bc27b56405252c3a027406d92 (refs/bisect/bad)
Author: Trond Myklebust <[email protected]>
Date: Mon Jan 27 09:58:19 2020 -0500
NFSv4: Limit the total number of cached delegations
Delegations can be expensive to return, and can cause scalability issues
for the server. Let's therefore try to limit the number of inactive
delegations we hold.
Once the number of delegations is above a certain threshold, start
to return them on close.
Signed-off-by: Trond Myklebust <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
[What could go wrong]
The fixes are restricted to NFS code, so problems should be limited to NFS
users. They could include performance issues, crashes, etc. Because these
changes are mostly related to NFS delegations, I use the `nfstest_delegation`
test suite from nfstest[*] to try and identify any regressions:
./nfstest_delegation --client 192.168.42.1 --server 192.168.42.2 -e
/srv/nfstest --trcdelay 4
Both before and after applying the fixes, I see the same 146 tests
pass and 23 failures. The 23 failures are expected because I was using
a Linux-based NFSv4 server which does not support all of the
delegation modes that the test checks for.
[*] git://git.linux-nfs.org/projects/mora/nfstest.git
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