I ran tests to compare disk performance of LVM versus normal ext3 partitions
on a hardware Raid 10 consisting of six 600G 10k physical disks. According to my
google search, I was expecting the performance to be about the same or a
tad bit slower for an LVM configuration.
The LVM consisted of 6 logical volumes on one volume group using the whole Raid 10.
The non-LVM consisted of 6 ext3 partitions on the Raid 10.
Can anyone explain why the LVM performed considerably better?
I was seeing a peek of 400k sectors/second on the LVM and
a peek of 234k sectors/second on the non-LVM.
a) Test consists of concurrent I/O of 24 large 2G files
b) Memory cache is cleared before each test
c) Disk cache is allowed to quiesce before each test
Large File Write Test
229 seconds - Dell R710 (LVM)
389 seconds - Dell R710 (no LVM)
Large File Read Test
296 seconds - Dell R710 (LVM)
521 seconds - Dell R710 (no LVM)
The write test consisted of writing 24 2G files using the dd command.
The read test consisted of copying those 24 2G files to /dev/null.