Btrfs RAID-10 performance
Miloslav Hůla
miloslav.hula at gmail.com
Tue Sep 8 12:25:06 EEST 2020
Thanks for the tips!
Dne 07.09.2020 v 15:24 Scott Q. napsal(a):
> 1. I assume that's a 2U format -24 bays. You only have 1 raid card for
> all 24 disks ? Granted you only have 16, but usually you should assign 1
> card per 8 drives. In our standard 2U chassis we have 3 hba's per 8
> drives. Your backplane should support that.
Exactly. And what's the reason/bottleneck? PCIe or card throughput?
> 2. Add more drives
We can add 2 next drives, and we actually did yesterday, but we keep
free slots to be able replace drives by double-capacity ones.
> 3. Get a pci nvme ssd card and move the indexes/control/sieve files there.
It complicates current backup and restore a little bit, but I'll
probably try that.
Thank you,
Milo
> On Monday, 07/09/2020 at 08:16 Miloslav Hůla wrote:
>
> Dne 07.09.2020 v 12:43 Sami Ketola napsal(a):
> >> On 7. Sep 2020, at 12.38, Miloslav Hůla <miloslav.hula at gmail.com
> <mailto:miloslav.hula at gmail.com>> wrote:
> >>
> >> Hello,
> >>
> >> I sent this into the Linux Kernel Btrfs mailing list and I got
> reply: "RAID-1 would be preferable"
> (https://lore.kernel.org/linux-btrfs/7b364356-7041-7d18-bd77-f60e0e2e2112@lechevalier.se/T/).
> May I ask you for the comments as from people around the Dovecot?
> >>
> >>
> >> We are using btrfs RAID-10 (/data, 4.7TB) on a physical
> Supermicro server with Intel(R) Xeon(R) CPU E5-2620 v4 @ 2.10GHz and
> 125GB of RAM. We run 'btrfs scrub start -B -d /data' every Sunday as
> a cron task. It takes about 50 minutes to finish.
> >>
> >> # uname -a
> >> Linux imap 4.9.0-12-amd64 #1 SMP Debian 4.9.210-1 (2020-01-20)
> x86_64 GNU/Linux
> >>
> >> RAID is a composition of 16 harddrives. Harddrives are connected
> via AVAGO MegaRAID SAS 9361-8i as a RAID-0 devices. All harddrives
> are SAS 2.5" 15k drives.
> >>
> >> Server serves as a IMAP with Dovecot 2.2.27-3+deb9u6, 4104
> accounts, Mailbox format, LMTP delivery.
> >
> > does "Mailbox format" mean mbox?
> >
> > If so, then there is your bottleneck. mbox is the slowest
> possible mailbox format there is.
> >
> > Sami
>
> Sorry, no, it is a typo. We are using "Maildir".
>
> "doveconf -a" attached
>
> Milo
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