[zfs-discuss] ZFS on RAID-5 array

Fajar A. Nugraha list at fajar.net
Sun Apr 15 23:07:47 EDT 2018


On Mon, Apr 16, 2018 at 12:58 AM, H via zfs-discuss
<zfs-discuss at list.zfsonlinux.org> wrote:
>>>>> Most posts until now seem to suggest a JBOD with ZFS on it and
>>>>> presumably setting asides two disks as hot-spares (if you can do that with
>>>>> ZFS.)

>>> So I should configure all 15 disks as one RAIDZ2 or three RAIDZ1 of five
>>> disks each?

> The disks are Hitachi enterprise-class disks but only 300 Gb each - does
> that change your recommendation?

As long as they're HDD (not SSD), the bottleneck will be on disk IOPS.
Enterprise or consumer HDD won't matter, if they have the same RPM.

I don't think you wrote your use case yet. There are cases where IOPS
won't matter much. Like when having only a single client writing
large, sequential file (e.g. video recording). In this case you might
be able to live with a single raidz2 array.

The other extreme is a busy database, where random read/write IOPS
matters a lot. In that case, even three raidz1 might not provide
enough IOPS for your needs.

-- 
Fajar


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