Chan Chung Hang Christopher wrote:
>
> Oh sorry, I have never argued about eight drive systems years ago
> (didn't have them then, too poor) and there is no argument about raid1+0
> being the way to do it beyond four drives. It is too obvious that
> stripping three drives and then mirroring them is more risky than making
> three mirrors and then stripping them. Any argument then about whether
> one should do raid0+1 were really limited to those who had four drive
> systems and never thought beyond four drives.
>
> So it is really moot unless one ignores the obvious or fails to think.
>
>> "Another difference between the two RAID configurations is performance
>> when the system is in a degraded state, i.e. after it has lost one or
>> more drives but has not lost the right combination of drives to
>> completely fail."
>>
>> RAID 1+0 is still more secure."
>>
> Hear, hear. Man, I should leave the 90s back there.
But note that drive capacity has gone up too, often eliminating the need
for many-disk arrays. For example, you can go up to 2TB on a single
drive, so a simple RAID1 mirror may be all you need, and if you can
arrange the mount points to match the use pattern you may get better
performance out of several separate raid1 partitions where the heads can
seek independently instead of essentially tying them all together in a
single array. A many-disk array may do better on artificial benchmarks
accessing one big file, but that's not what most computers actually do -
and raid1 has the advantages of not slowing down when a member fails and
you can recover the data from any single drive.
--
Les Mikesell
lesmikesell at gmail.com