lvcreate, extent based stripes, and pvgs

[Jim Krol]

I am trying to create a single lvol in a new Volume group, that will use extent based striping. The lvol will be the entire VG. If I use more than 2 PVGs i get the message
Not enough free physical extents available.
I am trying to use 5 PVGs. There are 2626 free extents on each PV, and one PV per PVG. Do I have to have more than one PV in a PVG. I am stuck with 5 PV so I can not use an even number of PVGs. This is the command I use to create the lvol:

lvcreate -n data1 -D y -s g -l 13100 /dev/vgWhse1dat1

I just want to have the date distributed by extent to each PV. What am I doing wrong.

Jim Krol

[Patrick Wallek · Accepted solution]

If you are not going to be mirroring, then ALL your PV's need to be in the same PVG. The lvcreate extend will distribute the volume across ALL PV's, extent by extent, in the SAME PVG.

The only time you would need multiple PVGs is if you are mirroring this extent/distributed LV.

In that case you would need 2 PV's and would need the '-s g' (I think) option to enable PVG-Strict mirror allocation so the mirror will be on a separate PVG from the original.

[Jim Krol]

To quote the imortal Homer J. Simpson, "DOH". That makes sense. You would use distributed allocation if you want to mirror. I have done that in the past. I could just use regular striping if I don't need to mirror. Thanks for the quick reply.

JK

[Jim Krol]

Thanks.
JK