m.brodbelt at acu.ac.uk
Wed Nov 15 18:17:52 GMT 2000
Shaun Lipscombe wrote:
> Apparently you can optimise performace by modifying the write cache if
> you are using raid-5 to that of the stripe size.
> 1) is this true (can't remember where I read it now!)
In theory, it can help, as your cache flush requests will then write an
entire stripe evenly. In practice, I wouldn't bother - any decent
hardware RAID card will have on card cache RAM, and will buffer requests
in that cache until it can write a stripe anyway, so I'd be very
surprised to see any difference at all.
> 2) how do I find the stripe size easily ( I am using hardware raid-5
> because software raid-5 was alpha when I put the box up 2 yrs ago)
SW RAID on Linux is actually pretty reliable - RAID 0.90 will be in the
shipping 2.4 kernel, and the "alpha" patches are actually very stable.
It's also faster on a decent CPU. Nevertheless, I prefer HW RAID where
possible - you get lots of nice features like hot-swap with a good raid
card, and power outages aren't necessarily as disastrous, as most decent
cards have battery backed cache.
More information about the samba-ntdom