A poll for opinions if I may? I've got a few gmirrors running on various machines, all of which pair up two drives at the physical level (i.e. mirror /dev/ad0s1 with /dev/ad1s1). Of course there are other ways of doing it to, like mirroring at the partition level, ie pairing /dev/ad0s1a with /dev/ad1s1a, /dev/ad0s1e with /dev/ad0s1e, etc. Apart from potentially avoiding a whole disk from being copied during a resync after a crash, are there any other advantages to using partition level mirroring instead of drive level mirroring? Joe -- === Josef Karthauser (joe@tao.org.uk) === http://x2obuilder.com/tao ==-------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 195 bytes Desc: not available Url : http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20070117/14b5d983/attachment.pgp
On 1/17/07, Josef Karthauser <joe@freebsd.org> wrote:> A poll for opinions if I may? > > I've got a few gmirrors running on various machines, all of which > pair up two drives at the physical level (i.e. mirror /dev/ad0s1 > with /dev/ad1s1). Of course there are other ways of doing it to, > like mirroring at the partition level, ie pairing /dev/ad0s1a with > /dev/ad1s1a, /dev/ad0s1e with /dev/ad0s1e, etc. > > Apart from potentially avoiding a whole disk from being copied > during a resync after a crash, are there any other advantages to > using partition level mirroring instead of drive level mirroring?I can imagine people using partition-level raid to implement a popular configuration: You divide a couple of identical drives proportionally in two partitions each, place a couple of the first partitions into gmirror and a couple of the second ones into gstripe. This way you get both reliable and fast storage with just two drives. Some strings are attached.
> Apart from potentially avoiding a whole disk from being copied > during a resync after a crash, are there any other advantages to > using partition level mirroring instead of drive level mirroring?Joe, Partition-level software RAID plus LVM is how the following Slashdot poster manages extendable (and inequally sized disk) arrays on Linux: http://ask.slashdot.org/comments.pl?sid=169386&cid=14117414 Best wishes, Matthew -- "Rogues are very keen in their profession, and know already much more than we can teach them respecting their several kinds of roguery." - A. C. Hobbs in _Locks and Safes_ (1853)