Tiernan,
Depending on how you have created your current pool, you *may* be able to add
the mirroring without rebuilding it. Each disk in the stripe can have a second
disk of equal size attached to it to form a mirrored component, or vdev. So if
your pool has 2 500GB drives, attach another 500GB drive to each, forming a
mirror of each stripe half.
# zpool status
pool: mypool
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
mypool ONLINE 0 0 0
c0t50d1 ONLINE 0 0 0
c0t50d2 ONLINE 0 0 0
errors: No known data errors
# zpool attach mypool c0t50d1 c0t50d3
# zpool attach mypool c0t50d2 c0t50d4
# zpool status
pool: mypool
state: ONLINE
scrub: resilver completed after 0h0m with 0 errors on Sat Jul 16 07:38:07 2011
config:
NAME STATE READ WRITE CKSUM
mypool ONLINE 0 0 0
mirror ONLINE 0 0 0
c0t50d1 ONLINE 0 0 0
c0t50d3 ONLINE 0 0 0
mirror ONLINE 0 0 0
c0t50d2 ONLINE 0 0 0
c0t50d4 ONLINE 0 0 0
errors: No known data errors
#
Both single vdevs (c0t50d1 and c0t50d2) are now mirrored.
If you don't have a second disk appropriately sized to match the current pool
members, you can create one or two pools with your two 500GB and two 300GB
disks,, depending on your needs.
Either:
# zpool create pool1 mirror <500GB-1> <500GB-2> mirror <300GB-1> <300GB-2>
to make one ~800GB pool. Or
# zpool create pool1 mirror <500GB-1> <500GB-2>
# zpool create pool2 mirror <300GB-1> <300GB-2>
to make two pools, one ~500GB and one ~300GB.
As long as the mirrored pairs match they do not have to be all the same in the
pool.
Craig
Tiernan OToole wrote:
> Thanks for the info. need to rebuild my machine and ZFS pool.... kind of new
> to this and realized i built it as a stripe, not a mirror... also, want to
> add extra disks...
>
> As a follow up question:
>
> I have 2 500Gb internal drives and 2 300Gb USB drives. If i where to create
> a 2 pools, a 300Gb and a 500Gb in each, and then mirror over them, would
> that work? is it even posible? or what would you recomend for that setup?
>
> Thanks.
>
> --Tiernan
>
> On Fri, Jul 15, 2011 at 5:39 PM, Edward Ned Harvey <
> opensolarisisdeadlongliveopensola...@nedharvey.com> wrote:
>
>> > From: zfs-discuss-boun...@opensolaris.org [mailto:zfs-discuss-
>> > boun...@opensolaris.org] On Behalf Of Tiernan OToole
>> >
>> > This might be a stupid question, but here goes... Would adding, say, 4 4
>> or
>> > 8gb usb keys as a zil make enough of a difference for writes on an iscsi
>> shared
>> > vol?
>> >
>> > I am finding reads are not too bad (40is mb/s over gige on 2 500gb drives
>> > stripped) but writes top out at about 10 and drop a lot lower... If I
>> where to
>> > add a couple usb keys for zil, would it make a difference?
>>
>> Unfortunately, usb keys, even the fastest ones, are slower than physical
>> hard drives. I even went out of my way to buy a super expensive super fast
>> USB3 16G fob... And it's still slower than a super-cheap USB2 sata hard
>> drive.
>>
>> There is a way you can evaluate the effect of adding a fast slog device
>> without buying one. (It would have to be a fast device, certainly no USB
>> fobs.) Just temporarily disable your ZIL. That's the fastest you can
>> possibly go. If it makes a big difference, then getting a fast slog device
>> will help you approach that theoretical limit. If it doesn't make a huge
>> difference, then adding slog will not do you any good.
>>
>> To disable ZIL, if your pool is sufficiently recent, use the zfs set sync=
>> command. It takes effect immediately. If you have an older system, you'll
>> have to use a different command, and you'll probably have to remount your
>> filesystem in order for the change to take effect.
>>
>>
>
>
> --
> Tiernan O'Toole
> blog.lotas-smartman.net
> www.tiernanotoolephotography.com
> www.the-hairy-one.com
> _______________________________________________
> zfs-discuss mailing list
> zfs-discuss@opensolaris.org
> http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
>
--
Craig Cory
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