8-way stripe but 16 disks reported ...

[Philip Kime]

Output below says it all - it says 8-way stripe but there are 16 disks listed (which makes sense because the LV is far too big for 8 disks). Is this just a messed up output from lvdisplay?

--- Logical volumes ---
LV Name /dev/vg01/lvol4
VG Name /dev/vg01
LV Permission read/write
LV Status available/syncd
Mirror copies 0
Consistency Recovery MWC
Schedule striped
LV Size (Mbytes) 163840
Current LE 40960
Allocated PE 40960
Stripes 8
Stripe Size (Kbytes) 64
Bad block NONE
Allocation strict
IO Timeout (Seconds) default

--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c3t0d0 2727 2727
/dev/dsk/c5t0d0 2727 2727
/dev/dsk/c7t0d1 2727 2727
/dev/dsk/c9t0d1 2727 2727
/dev/dsk/c3t0d2 2727 2727
/dev/dsk/c5t0d2 2727 2727
/dev/dsk/c7t0d3 2727 2727
/dev/dsk/c9t0d3 2727 2727
/dev/dsk/c3t0d4 2393 2393
/dev/dsk/c5t0d4 2393 2393
/dev/dsk/c7t0d5 2393 2393
/dev/dsk/c9t0d5 2393 2393
/dev/dsk/c3t0d6 2393 2393
/dev/dsk/c5t0d6 2393 2393
/dev/dsk/c7t0d7 2393 2393
/dev/dsk/c9t0d7 2393 2393

[Hoefnix]

Hi,

Check also "vgdisplay -v vg01" to see all the PV's and the different PV(PE) sizes.

First thing that came to my mind is that it's also reporting alternate path's but vgdisplay -v will clear this up.
If not post also the output of this command.

HTH,
Peter Geluk

[Philip Kime]

None of these are alternate paths. I know that this is the wrong output as I'm trying to make an exact copy machine (in terms of LVM layout) and you simply can't lvcreate an 8-way stripe of 163840Mb with 11.36Gb (EMC) disks!

But I'm confused as to why it says 8-way stripe and then lists 16 disks - other LVs on this system say 8-way and list 8!

[John Palmer]

Hi,

It seems as though this logical volume was originally created on the first set of 8 disks then extended onto the second set. There's nothing wrong with lvdisplay.

You can create a clone in exactly the same way...

lvcreate, make it zero size
lvextend onto first set of 8 disks
lvextend onto second set of 8 disks.

Regards,
John

[Philip Kime]

Sorry, been stupid - it was an 8-way stripe which was extended by another 8 disks ...

[Jeff Schussele]

Hi Phillip,

I agree with John. The stripe can be obtained/maintained *as long as* you keep the PV count a mutiple of that stripe value - i.e. you could have a 4 way stripe with 4, 8, 12, 16, etc disks.
Now this LV could have been created with 8 originally or even the 16. Just needs to be a multiple of the stripe count.

Rgds,
Jeff

[Gerhard Roets]

Just to add on to Jeffs comment.

If you extend this VG you will hae to extend it in multiples of 8 as well. Yes its a pain but thats the carry over from the original striping definition
Regards
Gerhard