Greetings,
Happy to hear you successfully performed pgBackRest for a 50TB DB. Out of
curiosity I would like to know your infrastructure settings.
1. The connectivity protocoal and bandwidth you used for your backend
storage ? Is it iSCSI, FC FCoE or GbE ? what's the exact reason for
the 26 Hours it took in the best case ? What factors may reduce 26 Hours to
much less time say 10 Hour or so for a 50 TB DB to backup destination ??
What to fine tune or deploy for a better performance?
2. It has been said that you are running the DB on a 2 slot 18 core
processor = 36 Physical cores .. Is it a dedicated Server H/W entirely
dedicated for a 50 TB database alone ?
Why I asked, nowadays mostly we may run the DB servers on VMs in
virtualized environments.. So I would like to know all 36 Physical cores
and associated RAM are all utilized by your 50 TB Database server ? or any
vacant CPU cores/Free RAM on those server machines?
3. What kind of connectivity/bandwidth between DB server and Storage
backend you established ( I Want to know the server NIC card details,
Connectivity Channel protocol/bandwidth and Connecting Switch spec from DB
Server to Storage backend( NAS in this case right ?)
Could you share the recommendations / details as in your case , Becoz I'm
also in need to perform such a pgBackRest trial from a production DB to
a suitable Storage Device( Mostly Unified storage DELL Unity)
Any inputs are most welcome.
Thanks,
Krishane
On Tue, Oct 3, 2023 at 12:14 PM Abhishek Bhola <
abhishek.bh...@japannext.co.jp> wrote:
> Hello,
>
> As said above, I tested pgBackRest on my bigger DB and here are the
> results.
> Server on which this is running has the following config:
> Architecture: x86_64
> CPU op-mode(s): 32-bit, 64-bit
> Byte Order: Little Endian
> CPU(s): 36
> On-line CPU(s) list: 0-35
> Thread(s) per core: 1
> Core(s) per socket: 18
> Socket(s): 2
> NUMA node(s): 2
>
> Data folder size: 52 TB (has some duplicate files since it is restored
> from tapes)
> Backup is being written on to DELL Storage, mounted on the server.
>
> pgbackrest.conf with following options enabled
> repo1-block=y
> repo1-bundle=y
> start-fast=y
>
>
> 1. *Using process-max: 30, Time taken: ~26 hours*
> full backup: 20230926-092555F
> timestamp start/stop: 2023-09-26 09:25:55+09 / 2023-09-27
> 11:07:18+09
> wal start/stop: 000000010001AC0E00000044 /
> 000000010001AC0E00000044
> database size: 38248.9GB, database backup size: 38248.9GB
> repo1: backup size: 6222.0GB
>
> 2. *Using process-max: 10, Time taken: ~37 hours*
> full backup: 20230930-190002F
> timestamp start/stop: 2023-09-30 19:00:02+09 / 2023-10-02
> 08:01:20+09
> wal start/stop: 000000010001AC0E0000004E /
> 000000010001AC0E0000004E
> database size: 38248.9GB, database backup size: 38248.9GB
> repo1: backup size: 6222.0GB
>
> Hope it helps someone to use these numbers as some reference.
>
> Thanks
>
>
> On Mon, Aug 28, 2023 at 12:30 AM Abhishek Bhola <
> abhishek.bh...@japannext.co.jp> wrote:
>
>> Hi Stephen
>>
>> Thank you for the prompt response.
>> Hearing it from you makes me more confident about rolling it to PROD.
>> I will have a discussion with the network team once about and hear what
>> they have to say and make an estimate accordingly.
>>
>> If you happen to know anyone using it with that size and having published
>> their numbers, that would be great, but if not, I will post them once I set
>> it up.
>>
>> Thanks for your help.
>>
>> Cheers,
>> Abhishek
>>
>> On Mon, Aug 28, 2023 at 12:22 AM Stephen Frost <sfr...@snowman.net>
>> wrote:
>>
>>> Greetings,
>>>
>>> * Abhishek Bhola (abhishek.bh...@japannext.co.jp) wrote:
>>> > I am trying to use pgBackRest for all my Postgres servers. I have
>>> tested it
>>> > on a sample database and it works fine. But my concern is for some of
>>> the
>>> > bigger DB clusters, the largest one being 50TB and growing by about
>>> > 200-300GB a day.
>>>
>>> Glad pgBackRest has been working well for you.
>>>
>>> > I plan to mount NAS storage on my DB server to store my backup. The
>>> server
>>> > with 50 TB data is using DELL Storage underneath to store this data
>>> and has
>>> > 36 18-core CPUs.
>>>
>>> How much free CPU capacity does the system have?
>>>
>>> > As I understand, pgBackRest recommends having 2 full backups and then
>>> > having incremental or differential backups as per requirement. Does
>>> anyone
>>> > have any reference numbers on how much time a backup for such a DB
>>> would
>>> > usually take, just for reference. If I take a full backup every Sunday
>>> and
>>> > then incremental backups for the rest of the week, I believe the
>>> > incremental backups should not be a problem, but the full backup every
>>> > Sunday might not finish in time.
>>>
>>> pgBackRest scales extremely well- what's going to matter here is how
>>> much you can give it in terms of resources. The primary bottle necks
>>> will be CPU time for compression, network bandwidth for the NAS, and
>>> storage bandwidth of the NAS and the DB filesystems. Typically, CPU
>>> time dominates due to the compression, though if you're able to give
>>> pgBackRest a lot of those CPUs then you might get to the point of
>>> running out of network bandwidth or storage bandwidth on your NAS.
>>> We've certainly seen folks pushing upwards of 3TB/hr, so a 50TB backup
>>> should be able to complete in less than a day. Strongly recommend
>>> taking an incremental backup more-or-less immediately after the full
>>> backup to minimize the amount of WAL you'd have to replay on a restore.
>>> Also strongly recommend actually doing serious restore tests of this
>>> system to make sure you understand the process, have an idea how long
>>> it'll take to restore the actual files with pgBackRest and then how long
>>> PG will take to come up and replay the WAL generated during the backup.
>>>
>>> > I think converting a diff/incr backup to a full backup has been
>>> discussed
>>> > here <https://github.com/pgbackrest/pgbackrest/issues/644>, but not
>>> yet
>>> > implemented. If there is a workaround, please let me know. Or if
>>> someone is
>>> > simply using pgBackRest for a bigger DB (comparable to 50TB), please
>>> share
>>> > your experience with the exact numbers and config/schedule of backups.
>>> I
>>> > know the easiest way would be to use it myself and find out, but since
>>> it
>>> > is a PROD DB, I wanted to get some ideas before starting.
>>>
>>> No, we haven't implemented that yet. It's starting to come up higher in
>>> our list of things we want to work on though. There are risks to doing
>>> such conversions though that have to be considered- it creates long
>>> dependencies on things all working because if there's a PG or pgBackRest
>>> bug or some way that corruption slipped in then that ends up getting
>>> propagated down. If you feel really confident that your restore testing
>>> is good (full restore w/ PG replaying WAL, running amcheck across the
>>> entire restored system, then pg_dump'ing everything and restoring it
>>> into a new PG cluster to re-validate all constraints, doing additional
>>> app-level review and testing...) then that can certainly help with
>>> mitigation of the risks mentioned above.
>>>
>>> Overall though, yes, people certainly use pgBackRest for 50TB+ PG
>>> clusters.
>>>
>>> Thanks,
>>>
>>> Stephen
>>>
>>
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