Re: [gentoo-server] RAID5 vs. RAID0+1

[Richard Broersma Jr]

> Firstly, forget 0+1, use RAID10.

I don't mean to hijack the tread but I have a related question.

I see from reading the mdadm man page that a RAID10 array can be created directly from individual
drives.  I assume this gives better performance than creating two raid1 arrays and then using
raid0 to attach the two raid1 meta devices.  Is this the case?

Also, I notice when building new kernels that there are no kernel modules for RAID10.  I haven't
yet tested this myself (although I have (4) 300GB on hand to start testing in the next few weeks),
but would this create a problem when trying to create/mount a RAID10 meta device?


> RAID5 is fast for reads, slow for writes, and you lose the capacity of 1 disk.
> RAID10 is *fast* for reads *and* writes, but you lose the capacity of half
> your disks.

I had a terrible experience with my array when it was configured as raid5.  It worked well for
samba shares with lots of reads and few writes, but when I tried to use it in a heavy write
environment,  the performance was terrible and the array would break and individual drive would
become out of sync.  mdadm would of course automatically re-sync the drives once the writes
completed.


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