[linux-lvm] Re: Parallel mirroring

[Diego Jacobi <jacobidiego@gmail.com>]

Hi.

Sry for retry but the lvm list is my last resource.

Does Linux-LVM have Parallel scheduler mode for mirroring at all?
If yes, how do you set it up, or check if it is enabled?

Thanks.
Diego



2009/7/12 Diego Jacobi <jacobidiego@gmail.com>:
> 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)
>