gmirror on different disks

[Adam Vande More]

On Fri, Jul 31, 2009 at 5:24 AM, Grzegorz Danecki <g.danecki at gmail.com>wrote:

> Hello everybody!
>
> I'm just wondering, I had gmirror with two disks:
>
> Master:  ad0 <ST3160815AS/4.AAB> Serial ATA II
> Master:  ad2 <ST3160815AS/4.AAB> Serial ATA II
>
> unfortunately ad0 failed today, leaving me with degraded array and ad0
> offline.
>
> I did
>
> # gmirror forget gm0, then shutdown, ad0 was replaced with:
>
> ad0: 152626MB <Seagate ST3160815AS 3.AAD> at ata0-master SATA300
>
> with different firmware I think.
>
> Then gmirror insert gm0 /dev/ad0
>
> (...)
> Jul 31 09:55:46 julia kernel: GEOM_MIRROR: Device gm0: rebuilding provider
> ad0 finished.
> Jul 31 09:55:46 julia kernel: GEOM_MIRROR: Device gm0: provider ad0
> activated.
>
> But the disk is a little bit smaller:
>
> 1. Name: mirror/gm0
>   Mediasize: 160040803328 (149G)
>   Sectorsize: 512
>   Mode: r5w5e6
> Consumers:
> 1. Name: ad2
>   Mediasize: 160041885696 (149G)
>   Sectorsize: 512
>   Mode: r1w1e1
>   State: ACTIVE
>   Priority: 0
>   Flags: DIRTY
>   GenID: 1
>   SyncID: 1
>   ID: 3791030614
> 2. Name: ad0
>   Mediasize: 160040803840 (149G)
>   Sectorsize: 512
>   Mode: r1w1e1
>   State: ACTIVE
>   Priority: 0
>   Flags: DIRTY
>   GenID: 1
>   SyncID: 1
>   ID: 2477089776
>
> # gmirror status
>      Name    Status  Components
> mirror/gm0  COMPLETE  ad2
>                      ad0
>
> so, it looks fine.
>
> Can I expect any problems now because of different sizes? Any problems when
> RAID will be almost full?
> I mean - should I make the RAID once again with exactly the same drives, or
> can I leave it as it is right now?
>
> Thanks in advance!
>  <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>
>

Drives don't matter to gmirror as long as they are at least big enough.  You
may get better performance with identical drives however.


-- 
Adam Vande More