On Mon, 12 Jul 1999, Paul Jakma wrote:
> On Mon, 12 Jul 1999, Joel Fowler wrote:
>
> Now, I would like to raid-1 my swap partition for high-availability. I
> read in the Software-Raid-HOWTO that as of 2.0.x that it wasn't supported
> and would cause crashes. Is that still the case with the 2.2.5-22 kernel?
> If it will work, is there a HOWTO, Recipe, etc. that describes the process
> of implementing raid on swap partitions? If not is there anyone who has
> done it on 2.2.5-22?
>
> I have swap on raid5:
>
Is there still that memory allocation problem in raid-code?
It whas there in 2.2.4.
I managed to hang the kernel by user level prosess that uses lot of
memory. Normally kernel kills that kind of prosess if I don't use swap in
raid4/5, but when I used swap on raid5 everything freezed.
<!--history-->
Problem was that raid-code tries to allocate memory when it write to
disk. Since there is no free page in memory, kernel tries to swap more and
we are in deadlock.
Notice that this problem doesn't occure if there is free memory left.
<--end of history-->
> Only set it up 2 days ago, but it's stable so far.
Have you use it in very heavy load and with prosesses which uses a lot of
memory.
> kernel 2.2.11pre, with raid0145 and the current->priority fix.
I Don't know how stable it is...
> works here. (so far, fingers crossed). My chunk size is probably a
> tad too large, the machine blocks noticable when swapping. For swap
> it'd probably be better to set it to 8 or 16k. (experimentation
> needed.)
Nowdays I use swap on raid1 and everything is fine. When server swaps
it slows normally but there is no blocking.
I use 4k-chunk size because if I remember correctly kernel uses
4k-swappages.
-->[EMAIL PROTECTED] [13.07.1999]
-<From the Linux-quote-collection>-
"Absolutely nothing should be concluded from these figures except that
no conclusion can be drawn from them."
(By Joseph L. Brothers, Linux/PowerPC Project)
