Expandable raid
I am setting up a system with five drives. Initially two will be for the system and three for other uses. In about 4-6 weeks the three will be added to the original two. Thoughts on picking a raid config to make this easy? I would like to use raid-10, but I don't see a way to grow it.
Kernel will be initially FC9 (whatever is shipping in the next few days), but a kernel.org 2.6.27 will be going in shortly in hopes that the changes to MTRR handling will allow a PAE kernel to use all of 8GB memory in 32 bit mode.
Signature · 3 lines
Bill Davidsen <[email protected]> "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark
Quoted 4 lines
I am setting up a system with five drives. Initially two will be for the system and three for other uses. In about 4-6 weeks the three will be added to the original two.
What does "added" mean here? Physically? Logically? If logically, in what way? And what's the starting point? If you start with 5 drives, why configure them initially as 2 arrays, and then merge later into 1 array? The exact array shapes involved matter.
Quoted 2 lines
Thoughts on picking a raid config to make this easy? I would like to use raid-10, but I don't see a way to grow it.
What's "this"? Do you want to end up with a 5-drive array? If so, where are you going to put the boot filesystem (most BIOSes require single drive boot filesystems) unless it is a 5 drive RAID1? In which case, growing is easy :-).
More generally, my usual story: growing an array is a dangerous and slow operation. Backup and restore is usually a lot faster, results in a better physical to logical layout, and safer (and one should backup anyhow before growing).
BTW I was just looking at his home page for other reasons (NFSv4) and noticed this:
"LaFS Log Structured File system for Linux - VERY alpha
Neil Brown 7 weeks ago RSS".
Quoted 11 lines · Peter Grandi
Quoted 4 lines
I am setting up a system with five drives. Initially two will be for the system and three for other uses. In about 4-6 weeks the three will be added to the original two.
What does "added" mean here? Physically? Logically? If logically, in what way? And what's the starting point? If you start with 5 drives, why configure them initially as 2 arrays, and then merge later into 1 array? The exact array shapes involved matter.
Means I have five drives and need three for a project so they can't be part of the original system configuration. I will put system on two, and add the others after the project requiring them is complete.
Quoted 9 lines
Quoted 3 lines
Thoughts on picking a raid config to make this easy? I would like to use raid-10, but I don't see a way to grow it.
What's "this"? Do you want to end up with a 5-drive array? If so, where are you going to put the boot filesystem (most BIOSes require single drive boot filesystems) unless it is a 5 drive RAID1? In which case, growing is easy :-).
I always put the boot filesystem on raid1, over the first two drives (as seen by the BIOS). That way if one fails the BIOS boots the other. Once the system is up I can have the rest of the data as I want it. Generally a 200-200MB boot partition is adequate, with MBR written to both drives.
Quoted 5 lines
More generally, my usual story: growing an array is a dangerous and slow operation. Backup and restore is usually a lot faster, results in a better physical to logical layout, and safer (and one should backup anyhow before growing).
If I had the resources for backup space I would have just put more drives in the box, used a bigger box, etc. I'm looking for proposed solutions to the problem I have, rather than ways to avoid having the problem if I had resources I don't have.
Quoted 8 lines
BTW I was just looking at his home page for other reasons (NFSv4) and noticed this:
"LaFS Log Structured File system for Linux - VERY alpha
Neil Brown 7 weeks ago RSS".
Not really very descriptive, the filesystem which interests me at the moment is the one Compaq released from their UNIX on Alpha o/s, Tru64 IIRC. It has the advantage of having been in enterprise use for about a decade, and gets good marks from people I actually know and trust. Compared to Reiser4, ZFS, and even XFS (from what I hear) it seems to offer good real world performance without guru-level tuning and initial setup.
Always interesting, of course.
Signature · 3 lines
Bill Davidsen <[email protected]> "Woe unto the statesman who makes war without a reason that will still be valid when the war is over..." Otto von Bismark