Matt wrote: >> You use elvtune to tweak it. Basically you just define the max length >> the write queue can be before attention will be given to reads and >> likewise for the read queue. man elvtune for more information. > > "[root at server ~]# elvtune /dev/hda > ioctl get: Invalid argument > > elvtune is only useful on older kernels; > for 2.6 use IO scheduler sysfs tunables instead.." > > Thats what I get. I did say: "I assume you are talking about Centos 3.x with the 2.4 kernel" For tweaking the io schedulers in 2.6, you need to mount the sysfs filesystem which is under /sys on RHEL4/Centos4. Play around with the values under /sys/block/devicename/queue/*.