Re: reducing the number of disks a RAID1 expects

2007-09-15 Thread J. David Beutel
Neil Brown wrote: 2.6.12 does support reducing the number of drives in a raid1, but it will only remove drives from the end of the list. e.g. if the state was 58604992 blocks [3/2] [UU_] then it would work. But as it is 58604992 blocks [3/2] [_UU] it won't. You could fai

Re: MD RAID1 performance very different from non-RAID partition

2007-09-15 Thread Jordan Russell
Iustin Pop wrote: > Maybe it's because md doesn't support barriers whereas the disks > supports them? In this case some filesystems, for example XFS, will work > faster on raid1 because they can't force the flush to disk using > barriers. It's an ext3 partition, so I guess that doesn't apply? I t

Re: MD RAID1 performance very different from non-RAID partition

2007-09-15 Thread Iustin Pop
On Sat, Sep 15, 2007 at 02:18:19PM +0200, Goswin von Brederlow wrote: > Shouldn't it be the other way around? With a barrier the filesystem > can enforce an order on the data written and can then continue writing > data to the cache. More data is queued up for write. Without barriers > the filesyst

Re: MD RAID1 performance very different from non-RAID partition

2007-09-15 Thread Goswin von Brederlow
Iustin Pop <[EMAIL PROTECTED]> writes: > On Sat, Sep 15, 2007 at 12:28:07AM -0500, Jordan Russell wrote: >> (Kernel: 2.6.18, x86_64) >> >> Is it normal for an MD RAID1 partition with 1 active disk to perform >> differently from a non-RAID partition? >> >> md0 : active raid1 sda2[0] >> 8193

Re: MD RAID1 performance very different from non-RAID partition

2007-09-15 Thread Iustin Pop
On Sat, Sep 15, 2007 at 12:28:07AM -0500, Jordan Russell wrote: > (Kernel: 2.6.18, x86_64) > > Is it normal for an MD RAID1 partition with 1 active disk to perform > differently from a non-RAID partition? > > md0 : active raid1 sda2[0] > 8193024 blocks [2/1] [U_] > > I'm building a search