detaching a mirror from a trans device -- safe?

Thanks to Michael Sullivan <mps@discomsys.com> and Darren Dunham

<ddunham@taos.com>. Both agreed that unmounting the file system first is

the best way to go. Since that's possible, that's what I plan to do. It

would probably be OK to sync and then detach, but I want to be 100% safe,

and these file systems are solely for use by the app, so once the app is

shut down, those file systems will be quiescent. The unmount adds some

piece-of-mind, and will potentially avoid some fsck complaints later.

Thanks,

-Adam

On Fri, 27 Oct 2000, Adam and Christine Levin wrote:

> Ok, I've got what I hope is an interesting question.

>

> We're using a multiple-mirror scheme to backup some sensitive data. The

> way we're doing it is like so:

>

> disk1 <-> disk2 are mirrored

> disk3 is attached to that mirror.

> disk4 is an additional disk.

>

> Every week, we detach disk3 and attach disk4. At any given time, we have

> a two-way mirror (disks 1&2), a third mirror piece that's only missing

> during the resync, and a fourth disk that's got a snapshot of the files.

>

> The question is this: we're using a trans device to take advantage of UFS

> logging (this is all DiskSuite 4.1 under Solaris 2.6, fully

> patched). We've got several small slices on various disks that are

> mirrored together to be the logging piece.

>

> Once I know the filesystem is quiescent (application has been fully shut

> down), can I just detach the third mirror piece? Should I unmount the

> filesystem, detach the mirror, and then remount the filesystem, just to be

> extra sure?

>

> Thanks,

> -Adam

>

>

>

S

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[3912 byte] By [CodeProf.com] at [2007-12-25 11:33:00]

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