Paul Clements wrote:
Herta Van den Eynde wrote:Thanks, Paul.
To linux, they are known as devices sd[c-h], which have been configured as raid 0+1:
# cat /proc/mdstat Personalities : [raid0] [raid1] read_ahead 1024 sectors md2 : active raid1 md1[1] md0[0] 106679168 blocks [2/2] [UU]
md0 : active raid0 sde1[2] sdd1[1] sdc1[0] 106679232 blocks 8k chunks
md1 : active raid0 sdh1[2] sdg1[1] sdf1[0] 106679232 blocks 8k chunks
unused devices: <none>
It's generally thought to be better to set this up as a RAID 1+0 (three raid1 devices striped together) but maybe there's a reason why you've opted for the RAID 0+1? (there's one less md device, I guess)...
When I need to add extra disks, e.g. in slots 3 and 12, I assume that
the disk in slot 3 will get device name /dev/sdf, and the disks in slots
9 through 12 will subsequently be known as /dev/sd[g-j]. How will that
affect the raid 0+1 config?
You may want to think about using the autodetection feature of md (or mdadm's UUID capability)... these would allow you to avoid messing things up if your drive letters shift on you...
--
Paul
Raid 1+0 definitely was and is on my wish list, but when I set up the initial systems, I had no time to play around and check things out. I was nervous about the potential impact of devices changing names, and figured that it'd be easier to manage with a raid 0+1, as it'd be easy to break the mirror and take it from there.
I've got a bit more time now, so I'll check out autodetection and uuid.
Kind regards,
Herta
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Herta Van den Eynde Toledo system management
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