How redistribute PE on different PV

[Wood_2]

Hello,

I've a big FS about 1,2 To on XP 512
The probleme, I've a lot of PE contigous to the same disk (I have 58 disks).
The I/O perf are realy poor, all the requeste are on same disks (10/58).

Is it possible to redistribute online the PE of the 10 disks to another pv.

Thank you for your help

Nicolas

[Robert-Jan Goossens]

Hi Nicolas,

pvmove - move allocated physical extents from one LVM physical volume to other physical volumes

Check the man page,

Hope this helps,
Robert-Jan

[Fred Ruffet]

In fact, you should have create LV striped on those disks (stripping is an option on LV creation). Now all you can do is to create new LVs and swap content. As long as you already have a used disk, it may now be hard to strip on all disks.

Looking further, you can ask yourself if LUNs are well designed on this array.

Regards,

Fred

[Bernhard Mueller]

Nicolas,

look at lvdisplay -v /dev/vgXYZ/lvolXYZ

maybe the lvol is striped? then you cannot change it. If it is not striped you change to "distributed extents", but that would require to mirror it and then remove the original (non-distributed) extents

man lvcreate will give you an idea

Regards,
Bernhard

[Wood_2]

Thank you.

It's not possible for me to destroy en create a new and restore the data.
I don't have enough space to mirror the disk.

To use lvchange -D y, i need to use /etc/lvmpvg, i think this is a good idea.
But the data contigous, will be always contigous.
Only the new data will be distributed.

Thank you for your help

[Bernhard Mueller]

Nicolas,

yes, that is why you need to "lvchange -D f" to force subsequent distributed allocation, then mirror the lvol so your mirror is distributed, then remove the non-distributed mirror. This is the only non-disruptive way of doing it. For anything else you will have to create new lvols and copy the data, but for new lvols you need some space as well, though not necessarily twice of what you have allocated now...

Regards,
Bernhard

[Thierry Poels_1]

hi,

as you are talking about an XP 512 tis are logical disks, not physical. So the 10 (logical) busy disks might still be spread over more physical disks in the XP 512, or less if you're unlucky.

Perhaps you need to look at the XP 512 instead of at the HPUX side:
- add more cache memory ??
- HP StorageWorks Performance Control XP ??
- HP StorageWorks Auto LUN XP ??
--> have a chat with HP.

good luck,
Thierry.