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FC60 and LVM

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Andrew Luis Arruza
Frequent Advisor

FC60 and LVM

I am using a mirror in the FC60. When I look at the ARRAY MANAGER for the FC60 I can see what disks are being mirrored.
When I am at the command line and do a lvmdisplay the mirror does not show up.
Is this 'normal' when the mirroring is being done by the FC60?
Thanks for any/all help.
Andy
It is, after all, a matter of survival!!
2 REPLIES
Bill McNAMARA_1
Honored Contributor

Re: FC60 and LVM

this is normal.
LVM does not do the mirroring.
more correctly, mirror disk UX
does not mirror the logical volumes.
The mirroring is done
by the FC60 controller.
The device file you get for your 'disk',
more correctly LUN, on the
FC60 is two disks in reality. Your host
sees it as one PV. The c ontroller gets one
write request in, and writes two write requests to
the disk.
LVM sends only one write. the FC60 sends 2
Thus, the FC60 is doing
hardware raid, not lvm doing software raid.


Later,
Bill
It works for me (tm)
Insu Kim
Honored Contributor
Solution

Re: FC60 and LVM

This is how FC60 works.

The disk array uses hardware mirroring, in which the disk array automatically synchronizes the two disk images, without user or operating system involvement. This is unlike the software mirriring(LVM), in which the host operating system software synchronizes the disk images.
Disk mirroring is used by RAID 1 and RAID 0/1 LUNs. A RAID 1 LUN consists of exactly two disks, a primary disk and a mirror disk.
A RAID 0/1 LUN consists of an even number of disks, half of which are primary disks and the other half are mirror disks. If a disk failes or becomes inaceesible, the remaining disk of the mirrored pair provides uniterrupted data access. After a failed disk is replaced, the disk array automatically rebuilds a copy of the data from its companion disk.

That's why lvdisplay doesn't show up mirror information.

Best regards.
Never say "no" first.