Move PE from one disk to another

[Ryan Ma]

I have some lv that I want to relocate their distribution on several disks. But the lv is striped.

I have tried command pvmove but it does not run on striped lv.

Is there any other way?

Thanks.

[harry d brown jr]

You have to BACKUP the FILESYSTEM , make your lv changes, then RESTORE your LV. That's the price of striping.

live free or die
harry

[Steven Sim Kok Leong]

Hi,

The way that works:

1) Backup data in filesystem on LV
2) lvremove the LV
3) lvcreate the LV with appropriate distribution
4) newfs filesystem on LV
5) Restore data in filesystem on LV

Hope this helps. Regards.

Steven Sim Kok Leong

[Ryan Ma]

Thanks all.

Just wonder if there is any other solution beside backup/restore.

[harry d brown jr]

Ryan,

Nope, sorry.

live free or die
harry

[Ryan Ma]

One more question.

Can I increase the no. of stripe of original lv if I have new pv added to the vg?

Thanks.

[James R. Ferguson]

Hi Ryan:

Yes, you can extend the stripped set. The caveat simply is that you will need to use an equal number of disks to extend as you have already stripped across.

Regards!

...JRF...

[harry d brown jr]

Like JRF said, if your current stripe is 3 disks, then you need to add three new disks to extend the LV.

live free or die
harry

[Bill McNAMARA_1]

I'm sure with mirrordisk that you can mirror a striped lv onto a single disk lv no problem.. then split and remove the original.

Although I must admit, I never tried..

Later,
Bill

[Ryan Ma]

JRF, Harry,

I have tried to increase the striped size of a LV but fail.

Can you tell me the step of doing so?

My step:
1. I original have a LV with stripe size 2.
2. I increase the size and specify the disks. It forces me to select two PV.
3. I choose one original disk and one new disk.
4. The result is I have a LV with the same stripe size 2 but cross 3 disks.

Conclusion:
Strip size cannot be changed just like I can't use pvmove with a striped LV.

Regards,
Ryan

[James R. Ferguson]

Hi Ryan:

If your original logical volume was striped across *two* disks then you will need to add *two* new ones to stipe across. This insures that the strict allocation policy is enforced.

Regards!

...JRF...

[Ryan Ma]

Bill,

That's what I get when trying to mirror and striped lv.

# lvextend -m 1 /dev/vg00/lvtest /dev/dsk/c2t6d0
Striped mirrors are not supported. To enable mirroring options (-m, -M, -c),
do not specify the striping options (-i, -I) when creating logical volumes.

Regards,
Ryan

[James R. Ferguson]

Hi (again) Ryan:

If you wish to mirror and "stripe" you can use distributed extent allocation. The combination is called "extent-based mirrored stripes". This mimics striping and adds mirroring. The "striping" is much less granular than true striping, but offers good performance. Have a look at the man pages for 'lvcreate' for more details.

Regards!

...JRF...