Unable to mirror logical volume

[john korterman]

Hi,
perhaps my previous entry was not detailed enough. When you have defined a volume, the mirror for that must reside on a physically separate disk. As you only have two disks in the vol. group and the volume already uses extents from both disks, it cannot be mirrored.

Your present config says:
--- Distribution of logical volume ---
PV Name LE on PV PE on PV
/dev/dsk/c1t15d0 2238 2238
/dev/dsk/c0t10d0 262 262

meaning that 2238 + 262 = 2500 extents
the 2500 are used for the 20000 mb volume, meaning that each extend = 8 mb

Most of the volume is physically located on c1t15d0. If you reduce your volume to only use the 2238 extents on c1t15d0 it will make a volume the size of 2238 x 8 = 17904 mb
Such an operation would free the 262 extents on c0t10d0, which you could add to the existing 1976. This adds up to 2238 extents, meaning that there would be exactly enough space on c0t10d0 for mirroring 17904mb

That is what I think is possible. I may have overlooked something, as I am not used to such big numbers. Perhaps you better wait for other suggestions.

regards,
John K.

[J.A.R. Karremans]

Hi both,

Okay, but what I don't get now: I do not need the allocated space on the second (mirror) volume anymore, this is left-over rubish from the previous mirror (the previous lvol10, sized 10G which has been deleted and re-created as an lvol10, sized 20G). Can't I just remove that rubish from the second disk and get enough space to establish a mirror with the new, good and nice lvol10 of 20G on the first disk??

[Jean-Louis Phelix]

Hi,

Perhaps you missed something ... There is *no* rubbish space for the old lvol10 ... It has been freed by lvremove, but you *don't* have enough space to create a 20Go mirrored lvol. *17904Mo* is your *maximum* allowed size.

Regards.

[J.A.R. Karremans]

I think I get the picture now.

Creating a 16G lvol on the first disk, leaves the second one alone, leaving enough space to mirror lvol10 from the first disk on the second disk.

The 10G lvol spans both the first and the second disk in this lvol...

Alrighty then! I get the major idea... I was just convinced that the second disk in the VG was a dedicated mirror-disk, having a hard-boundry on size, but such is clearly not the case. This put's John's remarks in more clear perspective as well!!

Thanx very much!