ZVOL on SSD pool as a special device for HDD pool

[mailinglists]

Hi guys,

i have two pools, one HDD and one SSD.
I want to speedup HDD pool by using zfs special device.
As there is no disk space on SSDs, to create new partitions, I wonder, can I just create a new ZVOL and use it as a special device for HDD pool.
Something like:

zfs create -s -V 42455040k rpool/hddpoolSpecialDevice
zpool add hddpool special /rpool/hddpoolSpecialDevice

I wonder will this system have any problems during bootup.
Are there any reasons not to do this? What do you guys think?

 

[LnxBil]

I wonder will this system have any problems during bootup.
Are there any reasons not to do this? What do you guys think?

It will work if you would use the correct block file path /dev/zvol/rpool/hddpoolSpecialDevice but you could run into dependecy problems. If the special device is not present if you import your will, it'll fail. I don't know if you could add dependency management into the zpool import logic.

 

[mailinglists]

Tnx for answer.
I will use such options only for non production setups.