Anup Shukla wrote:
Format and run the dd command again.
The speed is 130MB/s now.
It can vary a quite a bit depending on where you hit the disk. Remember,
what you are testing is just how fast dd can read from /dev/zero and
write to the file in a filesystem with 1k blocks. How that will map to
real performance is another matter.
Its a bit confusing.
Does LVM slow down things? Or i did something that is not really of any
relevance to check IO speed.
LVM adds very little overhead. The file and placement on disk can have
more to do with raw I/O bandwidth than anything else in this particular
scenario.
I used mkfs.ext3 -m0 -E stride=96 -O dir_index /dev/sdb1 ...
I have a RAID5 volume consisting of 6 disk with stripe size = 64k
I hope the stride=96 is optimal.
Depends what you want... With 4k blocks in ext3 (default) a stride of 16
(16 times 4 is 64) would read one stripe from a disk. With 6 disk 16
times 6 is 96, so for every I/O you will hit each disk once and read one
stripe. Ditto for writes. In general that is a good start.
Should i stick with LVM, or go back to the older way?
I would never really consider not using LVM. The flexibility it adds for
disk management is essential for managing your disks.
//Morten
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