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Does VxVM work with a "disk snapshot which is a block device"

Level 3


We have a dg with a single physical disk that has "cdsdisk" format. I created a snapshot device (block device) SNAP_BLOCK_DEV for this physical disk. This snapshot device contains same data as on the physcial disk (there is one-to-one mapping).

Now, I want to show this snapshot device to VxVM i.e. want VxVM to work with thin snapshot device (block device). Is there a way? I tried following approach:

- Added SNAP_BLOCK_DEV as a "foreigndevice". After this I see "SNAP_BLOCK_DEV" in "vxdisk list" but it shows up as "Simple" disk and in "invalid" state. I want my SNAP_BLOCK_DEV to be seen by VxVM as a "cdsdisk" and "online valid" state and my data still intact. Is there a way?

- Is there a way to tell VxVM to look up/scan for devices in a specific directory (other than foreigndevice mechanism)? Does VxVM scan only physical devices? or it can also scan and work with block devices?


Level 6

Hi Sunil,

I'm the forum admin, and you can always PM me directly via my profile Kimberley. In this case, Gaurav and Marianne are giving you the best way to get your question answered, as I'm not a product expert by any mean.

Marianne has provided Support instructions above, and here is a screenshot to show where on the site you'll find those links:

Also, here is the link for phone support:

Hope this helps. Best,

Community Admin

Level 4

i think the crux of the problem is you are using cdsdisk

cdsdisk is only supported on disk drives which will return scsi sense mode ioctl command

scsi sense mode command is used to get the disk geometry without querying the disk partition table.

obviously your block device wont support it

so i dont think you will be able to get cdsdisk working with block device.

you may have better luck if you had initiatlized the original disk as sliced disk. so vxdisk scan will read the disk geometry from the disk media itself rather than from disk firmware/bios