Quorums!! What is the meaning ,

[municipal]

Hi All
I do not understand the Quorum by defintion
can somebody explain it or where can I find more info
TIA.

 

[ogniemi]

quorum says the VG will be active (variedon) when you have it met. so, having 8 logical disks in the VG you have 9 VGDAs copies (one disk has 2 copies) and then quorum is 8/2 + 1 = 5. I fou would lost 4 disks (but not including the disk having 2 VGDAs) the the VG will still be active. Bt if one of the 4 disks is the disk having 2 VGDA the quorum will be lost and the VG will be deactivated.

I also noticed that having LVM mirroring built on 2 RAID5 arrays (each array built of 8 disks in my test env) the quorum is set to 2 (MAX VGDA = 3 not 17)

that is my understanding of the quorum

r, m.

 

[alexhu]

another definition

a quorum is a vote of the number of VGDAs & VGSAs that are active. you have got to have 51% majority of VGDA/VGSA areas to keep the quorum unless of course you turn off the quorum check. each disk has at least one VGDA/VGSA. in the case of a VG that has only two disks, one of them has two VGDA/VGSA areas and the other has one VGDA/VGSA. and of course if you only have one PV in a VG, it would contain two VGDA/VGSA areas...

Clear as mud ?

Alex

 

[municipal]

Thanks