gmirror confusion
Ken Gunderson
kgunders at teamcool.net
Sun Dec 12 15:27:58 PST 2004
On Friday 10 December 2004 07:47 pm, Ken Gunderson wrote:
> Hello:
>
> Been fighting gmirror for longer than I want to admit and going to
> have to break down and ask for help on what at first blush seems
> should be trivial... Would somebody please elaborate upon Pawel's
> post in the gmirror problmes thread:
>
> <pjb>
> The safest way to do what you want is to:
>
> # gmirror label <name> ad1
> create slices and partitions on /dev/mirror/<name>
> create file system
> copy data from ad0 to <name>
> change /etc/fstab to boot from /dev/mirror/<name>s1a or
> something
> reboot
> # gmirror insert <name> ad0
> </pjb>
>
> I have two disks, ad0 and ad2 that I'd like to mirror. In the past
> would have just bootstrapped vinum. Gmirror seems like a better way
> to go for this type of application but I'm only recently using 5.3 on
> production machines so haven't had the chance to become as familiar
> with geom as I probably should be.
>
> I can get the mirror configured with the live files system trick, but
> not the above, which Pawel mentions as the "safest" way to handle
> this.
>
> For example, I've searched archives and seen references to both
>
> 1) "create slices and partitions on /dev/mirror/<name>"
>
> as well as
>
> 2) "create slices and partitions on provider"
>
> As well as confusion about whether the mirror's label should have the
> 16 sector offset thrown at it by bsdlabel, or whether I should just
> clone the label from the drive I did the install on.
>
> I'm also curious whether anyone has done any performance testing of
> the different balance options. For booting from 2 mirrored drives, I
> assume either "load" or "round-robin" would be the options of choice?
>
> TIA--
I'll be lame and follow up my own post... First, sorry that I confused
"provider" with "consumer", so that question is moot. However, I note
the following:
>>>>>>>
build# bsdlabel mirror/mirror0s1
# /dev/mirror/mirror0s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 524288 0 4.2BSD 2048 16384 32776
b: 4194304 524288 swap
c: 78156162 0 unused 0 0 # "raw" part,
don't edit
d: 1048576 4718592 4.2BSD 2048 16384 8
e: 1048576 5767168 4.2BSD 2048 16384 8
f: 8388608 6815744 4.2BSD 2048 16384 28552
g: 16777216 15204352 4.2BSD 2048 16384 28552
h: 46174594 31981568 4.2BSD 2048 16384 28552
build# bsdlabel /dev/mirror/mirror0s1
# /dev/mirror/mirror0s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 524288 63 4.2BSD 2048 16384 32776
b: 4194304 524351 swap
c: 78156162 63 unused 0 0 # "raw" part,
don't edit
d: 1048576 4718655 4.2BSD 2048 16384 8
e: 1048576 5767231 4.2BSD 2048 16384 8
f: 8388608 6815807 4.2BSD 2048 16384 28552
g: 16777216 15204415 4.2BSD 2048 16384 28552
h: 46174594 31981631 4.2BSD 2048 16384 28552
partition c: partition extends past end of unit
bsdlabel: partition c doesn't start at 0!
bsdlabel: An incorrect partition c may cause problems for standard
system utilities
partition h: partition extends past end of unit
<<<<<<<<<<<<<<<<<<<
Per man page for bsd label:
"When specifying the device, the /dev/ path prefix may be omitted; the
bsdlabel utility will automatically prepend it."
Hence I was getting confused about seeming eratic bsdlabels, until I
figured out that the return was consistent, but dependent upon whether
I prepended "/dev" or not, at least when applied to gmirror provider.
Is this 1) a bsdlabel or gmirror issue, and 2) which return should I
believe?
Thanks.
--
Best regards,
Ken Gunderson
GPG Key-- 9F5179FD
"Freedom begins between the ears." -- Edward Abbey
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