Adrian Chadd wrote:
On Tue, Sep 19, 2006, Micha? Margula wrote:
Hello!
I have a aufs on /dev/sdc. Iowait takes about 40% of CPU. If I add
another disk, will it make that load lower? Is it good idea to use two
disks with aufs (diskd is unstable unfortunately)?
Yes, AUFS is fine.
Take a look at http://www.squid-cache.org/~adrian/coss/ - note the dramatic
drop in IOWAIT when using COSS.
It also depends on the hardware you're using. What kind of disks are they?
Which OS? Which controller?
Linux 2.6.15.1, /dev/sdc with cache is Seagate ST336754LC (Cheetach) -
36 GB, 15k RPMs, and logging is done on /dev/md0 which is RAID1
consisting of two disks like the one above. But I don't think RAID1
causes any trouble, iostat shows majority of IO operations on /dev/sdc
where cache resides.
Hardware is 2 x Xeon 3.6, 2GB RAM, SCSI storage controller: LSI Logic
53c1030 PCI-X Fusion-MPT Dual Ultra320 SCSI on Intel E7520.
Now in topic of COSS, what is better solution (/dev/sdc is 36 GB and
/dev/sdd also will be 36 GB, same disk model):
1) /dev/sdc and /dev/sdc used in full with AUFS and 1GB file of COSS in
memory
2) /dev/sdc with AUFS and /dev/sdd with COSS (wouldn't be 36 GB too much?)
3) /dev/sdc splitted for COSS and AUFS (if yes, what ratio of
splitting), /dev/sdd with AUFS
4) /dev/sdc and /dev/sdd splitted for COSS and AUFS
I thought that (1) would be OK. What do you think? What is recommended
size of COSS file?
--
Michał Margula, alchemyx@xxxxxxxxxxxx, http://alchemyx.uznam.net.pl/
"W życiu piękne są tylko chwile" [Ryszard Riedel]
