Date: Sun, 6 Mar 2016 06:49:36 -0800 From: Richard Elling <richard.elling@richardelling.com> To: smartos-discuss@lists.smartos.org Cc: developer <developer@open-zfs.org>, "developer@lists.open-zfs.org" <developer@lists.open-zfs.org>, illumos-developer <developer@lists.illumos.org>, omnios-discuss <omnios-discuss@lists.omniti.com>, Discussion list for OpenIndiana <openindiana-discuss@openindiana.org>, illumos-zfs <zfs@lists.illumos.org>, "zfs-discuss@list.zfsonlinux.org" <zfs-discuss@list.zfsonlinux.org>, "freebsd-fs@FreeBSD.org" <freebsd-fs@FreeBSD.org>, "zfs-devel@freebsd.org" <zfs-devel@freebsd.org> Subject: Re: [smartos-discuss] an interesting survey -- the zpool with most disks you have ever built Message-ID: <5158F354-9636-4031-9536-E99450F312B3@RichardElling.com> In-Reply-To: <A5A6EA4AE9DCC44F8E7FCB4D6317B1D203178F1DD392@SH-MAIL.ISSI.COM> References: <95563acb-d27b-4d4b-b8f3-afeb87a3d599@me.com> <CACTb9pxJqk__DPN_pDy4xPvd6ETZtbF9y=B8U7RaeGnn0tKAVQ@mail.gmail.com> <CAJjvXiH9Wh%2BYKngTvv0XG1HtikWggBDwjr_MCb8=Rf276DZO-Q@mail.gmail.com> <56D87784.4090103@broken.net> <A5A6EA4AE9DCC44F8E7FCB4D6317B1D203178F1DD392@SH-MAIL.ISSI.COM>
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> On Mar 3, 2016, at 8:35 PM, Fred Liu <Fred_Liu@issi.com> wrote: >=20 > Hi, >=20 > Today when I was reading Jeff's new nuclear weapon -- DSSD D5's CUBIC = RAID introduction, > the interesting survey -- the zpool with most disks you have ever = built popped in my brain. We test to 2,000 drives. Beyond 2,000 there are some scalability issues = that impact failover times. We=E2=80=99ve identified these and know what to fix, but need a real = customer at this scale to bump it to the top of the priority queue. >=20 > For zfs doesn't support nested vdev, the maximum fault tolerance = should be three(from raidz3). Pedantically, it is N, because you can have N-way mirroring. > It is stranded if you want to build a very huge pool. Scaling redundancy by increasing parity improves data loss protection by = about 3 orders of=20 magnitude. Adding capacity by striping reduces data loss protection by = 1/N. This is why there is not much need to go beyond raidz3. However, if you do want to go there, = adding raidz4+ is=20 relatively easy. =E2=80=94 richard -- Richard.Elling@RichardElling.com +1-760-896-4422
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