Hello.
I have succesfully configured Mirroring between 2 disks in linux for 2
logical volumes, and on other without mirroring.
But i can not find any evidence showing that it is reading in parallel
scheduler mode.
I have read HP docs about HP-UX, but it talks about command line
options which arent in the linux side.
The "-d p" in HP-UX would be what i need now for linux. Also lvdisplay
doesnt show anything about it, more than the number of mirrors.
This are my tests:
sda1 = /boot in disk 1, no lvm
sdb1 = /boot in disk 2, no lvm
data/data = lvm without mirroring
data/root = lvm with mirroring
linux-8mmd:~ # hdparm -t /dev/sda1
/dev/sda1:
Timing buffered disk reads: 262 MB in 3.02 seconds = 86.83 MB/sec
linux-8mmd:~ # hdparm -t /dev/sdb1
/dev/sdb1:
Timing buffered disk reads: 174 MB in 3.03 seconds = 57.36 MB/sec
linux-8mmd:~ # hdparm -t /dev/data/data
/dev/data/data:
Timing buffered disk reads: 272 MB in 3.02 seconds = 90.02 MB/sec
linux-8mmd:~ # hdparm -t /dev/data/root
/dev/data/root:
Timing buffered disk reads: 278 MB in 3.02 seconds = 92.16 MB/sec
As you can see, the read speed are mostly the same. This could mean a
secuenced scheduler.
And this is my system setup:
lvm> version
LVM version: 2.02.39 (2008-06-27)
Library version: 1.02.27 (2008-06-25)
Driver version: 4.14.0
linux-8mmd:~ # pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 data lvm2 a- 537.11G 395.12G
/dev/sda5 data lvm2 a- 996.00M 988.00M <--- Note 1 Gb, for log
/dev/sdb3 data lvm2 a- 138.99G 118.99G
linux-8mmd:~ # lvs -a -o +devices
LV VG Attr LSize Origin Snap% Move Log
Copy% Convert Devices
data data -wi-ao 121.50G
/dev/sda3(125)
home data mwi-ao 10.00G home_mlog
100.00 home_mimage_0(0),home_mimage_1(0)
[home_mimage_0] data iwi-ao 10.00G
/dev/sda3(33788)
[home_mimage_1] data iwi-ao 10.00G
/dev/sdb3(2560)
[home_mlog] data lwi-ao 4.00M
/dev/sda5(1)
root data mwi-ao 10.00G root_mlog
100.00 root_mimage_0(0),root_mimage_1(0)
[root_mimage_0] data iwi-ao 10.00G
/dev/sda3(31228)
[root_mimage_1] data iwi-ao 10.00G
/dev/sdb3(0)
[root_mlog] data lwi-ao 4.00M
/dev/sda5(0)
test data -wi-a- 500.00M
/dev/sda3(0)
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