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From: "Vincent Olivier" <vincent@up4.com>
To: linux-btrfs@vger.kernel.org
Subject: RAID10 Balancing Request for Comments and Advices
Date: Tue, 16 Jun 2015 08:09:17 -0400 (EDT)	[thread overview]
Message-ID: <1434456557.89597618@apps.rackspace.com> (raw)

Hello,

I have a Centos 7 machine with the latest EPEL kernel-ml (4.0.5) with a 6-disk 4TB HGST RAID10 btrfs volume. With the following mount options :

noatime,compress=zlib,space_cache 0 2


"btrfs filesystem df” gives :


Data, RAID10: total=7.08TiB, used=7.02TiB
Data, single: total=8.00MiB, used=0.00B
System, RAID10: total=7.88MiB, used=656.00KiB
System, single: total=4.00MiB, used=0.00B
Metadata, RAID10: total=9.19GiB, used=7.56GiB
Metadata, single: total=8.00MiB, used=0.00B
GlobalReserve, single: total=512.00MiB, used=0.00B


My first question is this : is it normal to have “single” blocks ? Why not only RAID10? I don’t remember the exact mkfs options I used but I certainly didn’t ask for “single” so this is unexpected.

My second question is : what is the best device add / balance sequence to use if I want to add 2 more disks to this RAID10 volume? Also is a balance necessary at all since I’m adding a pair?

My third question is: given that this file system is an offline backup for another RAID0 volume with SMB sharing, what is the best maintenance schedule as long as it is offline? For now, I only have a weekly cron scrub now, but I think that the priority is to have it balanced after a send-receive or rsync to optimize storage space availability (over performance). Is there a “light” balancing method recommended in this case?

My fourth question, still within the same context: are there best practices when using smartctl for periodically testing (long test, short test) btrfs RAID devices?

Thanks!

Vincent

next             reply	other threads:[~2015-06-16 12:09 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-16 12:09 Vincent Olivier [this message]
2015-06-16 12:25 ` RAID10 Balancing Request for Comments and Advices Hugo Mills
2015-06-16 13:34   ` Vincent Olivier
2015-06-16 23:58     ` Duncan
2015-06-17  0:14       ` Chris Murphy
2015-06-17 13:13         ` Vincent Olivier
2015-06-17 13:27           ` Hugo Mills
2015-06-17 13:29             ` Vincent Olivier
2015-06-18  4:37             ` Duncan
2015-06-17 13:46       ` Vincent Olivier
2015-06-18  8:00         ` Duncan

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