Date: Mon, 25 Jun 2007 20:00:05 +0400 (MSD) From: Dmitry Morozovsky <marck@rinet.ru> To: Pawel Jakub Dawidek <pjd@freebsd.org> Cc: current@freebsd.org Subject: Re: ZFS questions Message-ID: <20070625194305.V32086@woozle.rinet.ru> In-Reply-To: <20070625153637.GA10643@garage.freebsd.pl> References: <20070625113541.Y68481@woozle.rinet.ru> <20070625153637.GA10643@garage.freebsd.pl>
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On Mon, 25 Jun 2007, Pawel Jakub Dawidek wrote:
PJD> On Mon, Jun 25, 2007 at 11:53:43AM +0400, Dmitry Morozovsky wrote:
PJD> > Dear colleagues,
PJD> >
PJD> > I'm playing with ZFS thinking about future storage server
PJD> > I have two questions about it (currently; a least ;-)
PJD> >
PJD> > 1. How can one determine which portion of a provider zpool uses? It seems
PJD> > logical for me if `zpool status -v' would display this info.
PJD>
PJD> I'm sorry, but I don't understand the question. If you use only one
PJD> partition of a disk, zpool status will show you which partition it is.
PJD> (but I don't think this was your question)
I was not clear enough. In my experiments I used disks of different sizes, and
got strange (to me) resulting sizes, such as:
marck@woozlie:~# diskinfo ad{6,8,10,12,14}
ad6 512 80026361856 156301488 155061 16 63
ad8 512 80026361856 156301488 155061 16 63
ad10 512 400088457216 781422768 775221 16 63
ad12 512 250059350016 488397168 484521 16 63
ad14 512 320072933376 625142448 620181 16 63
marck@woozlie:~# zpool create tank raidz ad6 ad8 ad12
marck@woozlie:~# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
tank 222G 189K 222G 0% ONLINE -
marck@woozlie:~# zpool status
pool: tank
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1 ONLINE 0 0 0
ad6 ONLINE 0 0 0
ad8 ONLINE 0 0 0
ad12 ONLINE 0 0 0
errors: No known data errors
marck@woozlie:~# zfs list
NAME USED AVAIL REFER MOUNTPOINT
tank 120K 146G 24.0K /tank
why zpool in 222G? zfs seems to have more reasonable size of 146G (sum of 2*80G
disks).
Next (replacing first 80G to 320G):
marck@woozlie:~# zpool replace tank ad6 ad14
[wait]
marck@woozlie:~# zpool status
pool: tank
state: ONLINE
scrub: resilver completed with 0 errors on Mon Jun 25 19:52:09 2007
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1 ONLINE 0 0 0
ad14 ONLINE 0 0 0
ad8 ONLINE 0 0 0
ad12 ONLINE 0 0 0
errors: No known data errors
marck@woozlie:~# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
tank 222G 363K 222G 0% ONLINE -
marck@woozlie:~# zfs list
NAME USED AVAIL REFER MOUNTPOINT
tank 120K 146G 24.0K /tank
Still the same sizes...
The last component (80G -> 400G):
marck@woozlie:~# zpool replace tank ad8 ad10
marck@woozlie:~# zpool status
pool: tank
state: ONLINE
scrub: resilver completed with 0 errors on Mon Jun 25 19:54:42 2007
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1 ONLINE 0 0 0
ad14 ONLINE 0 0 0
ad10 ONLINE 0 0 0
ad12 ONLINE 0 0 0
errors: No known data errors
marck@woozlie:~# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
tank 222G 354K 222G 0% ONLINE -
marck@woozlie:~# zfs list
NAME USED AVAIL REFER MOUNTPOINT
tank 120K 146G 24.0K /tank
Still the same. [final is at the end]
PJD>
PJD> > 2. It is also possible to expand the array by iteratively swapping each drive
PJD> > in the array with a bigger drive and waiting for ZFS to heal itself - the heal
PJD> > time will depend on amount of store information, not the disk size.
PJD> > [ http://en.wikipedia.org/wiki/ZFS#Limitations ]
PJD> >
PJD> > My experiments does not show that zpool size increases after set of
PJD> > `zpool replace'. Where did I went wrong?
PJD>
PJD> Works here after zpool export/zpool import.
Well, will check this. However, this means that pool size increasing requires
pool stopping (downtime required). Still much better than backup/restore or
even copying multi-terabyte fs...
In my case, though, numbers are still strange:
marck@woozlie:~# zpool export tank
marck@woozlie:~# zpool list
no pools available
marck@woozlie:~# zpool import
pool: tank
id: 5628286796211617744
state: ONLINE
action: The pool can be imported using its name or numeric identifier.
config:
tank ONLINE
raidz1 ONLINE
ad14 ONLINE
ad10 ONLINE
ad12 ONLINE
marck@woozlie:~# zpool import tank
marck@woozlie:~# zpool status
pool: tank
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
tank ONLINE 0 0 0
raidz1 ONLINE 0 0 0
ad14 ONLINE 0 0 0
ad10 ONLINE 0 0 0
ad12 ONLINE 0 0 0
errors: No known data errors
marck@woozlie:~# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
tank 698G 207K 698G 0% ONLINE -
marck@woozlie:~# zfs list
NAME USED AVAIL REFER MOUNTPOINT
tank 128K 458G 24.0K /tank
Strange: 458G or 698G? 320+250 does not look similar to either number....
Thanks!
Sincerely,
D.Marck [DM5020, MCK-RIPE, DM3-RIPN]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru ***
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