Adding -performance back in so others can learn.
On Apr 26, 2007, at 9:40 AM, Paweł Gruszczyński wrote:
Jim Nasby napisał(a):
On Apr 25, 2007, at 8:51 AM, Paweł Gruszczyński wrote:
where u6 stores Fedora Core 6 operating system, and u0 stores 3
partitions with ext2, ext3 and jfs filesystem.
Keep in mind that drives have a faster data transfer rate at the
outer-edge than they do at the inner edge, so if you've got all 3
filesystems sitting on that array at the same time it's not a fair
test. I heard numbers on the impact of this a *long* time ago and
I think it was in the 10% range, but I could be remembering wrong.
You'll need to drop each filesystem and create the next one go get
a fair comparison.
I thought about it by my situation is not so clear, becouse my hard
drive for postgresql data is rather "logical" becouse of RAID array
i mode 1+0. My RAID Array is divided like this:
Device Boot Start End Blocks Id System
/dev/sda1 1 159850 163686384 83 Linux
/dev/sda2 159851 319431 163410944 83 Linux
/dev/sda3 319432 478742 163134464 83 Linux
and partitions are:
/dev/sda1 ext2 161117780 5781744 147151720 4% /fs/ext2
/dev/sda2 ext3 160846452 2147848 150528060 2% /fs/ext3
/dev/sda3 jfs 163096512 3913252 159183260 3% /fs/jfs
so if RAID 1+0 do not change enything, JFS file system is at third
partition wich is at the end of hard drive.
Yes, which means that JFS is going to be at a disadvantage to ext3,
which will be at a disadvantage to ext2. You should really re-perform
the tests with each filesystem in the same location.
What about HDD with two magnetic disk`s? Then the speed depending
of partition phisical location is more difficult to calculate ;)
Propably first is slow, secund is fast in firs halt and slow in
secund halt, third is the fastes one. In both cases my JFS partitin
should be ath the end on magnetic disk. Am I wrong?
I'm not a HDD expert, but as far as I know the number of platters
doesn't change anything. When you have multiple platters, the drive
essentially splits bytes across all the platters; it doesn't start
writing one platter, then switch to another platter.
--
Jim Nasby jim@xxxxxxxxx
EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
