Is it possible to convert dataset to sparse volume (thin provisioning)

thin-provisioningzfs

I've created ZFS datasets and installed virtual servers into them. Suddenly my ZFS volume free space is gone, but not all space is used in each dataset. I want to introduce thin provisioning (use ZFS sparse volume).

Is it possible to convert datasets into sparse volumes without deleting them? Thanks.

Best Answer

As far as I know it's not possible to convert an existing zvol to sparse; they must be created sparse to begin with.

However, you can create a new sparse zvol, and zfs send from the old one and zfs recv to the new one, and then swap their names.

Related Solutions

ZFS, SAN’s, HA, Possible

I know that Nexenta does HA by using RSF-1 from http://high-availability.com/ - something you may want to consider is actually getting two NexentaStor head nodes which would bring all this goodness to you. If you're in the UK take a look at http://www.va-technologies.com/

Solaris ZFS volumes: workload not hitting L2ARC

You should have more RAM in the system. Pointers to L2ARC need to be kept in RAM (ARC), so I think you'd need around 4GB or 6GB of RAM to better utilize the ~60GB of L2ARC you have available.

This is from a recent thread on the ZFS list:

http://opensolaris.org/jive/thread.jspa?threadID=131296

L2ARC is "secondary" ARC. ZFS attempts to cache all reads in the ARC 
(Adaptive Read Cache) - should it find that it doesn't have enough space 
in the ARC (which is RAM-resident), it will evict some data over to the 
L2ARC (which in turn will simply dump the least-recently-used data when 
it runs out of space). Remember, however, every time something gets 
written to the L2ARC, a little bit of space is taken up in the ARC 
itself (a pointer to the L2ARC entry needs to be kept in ARC). So, it's 
not possible to have a giant L2ARC and tiny ARC. As a rule of thumb, I 
try not to have my L2ARC exceed my main RAM by more than 10-15x (with 
really bigMem machines, I'm a bit looser and allow 20-25x or so, but 
still...). So, if you are thinking of getting a 160GB SSD, it would be 
wise to go for at minimum 8GB of RAM. Once again, the amount of ARC 
space reserved for a L2ARC entry is fixed, and independent of the actual 
block size stored in L2ARC. The jist of this is that tiny files eat up 
a disproportionate amount of systems resources for their size (smaller 
size = larger % overhead vis-a-vis large files).

Best Answer

Related Solutions

ZFS, SAN’s, HA, Possible

Solaris ZFS volumes: workload not hitting L2ARC

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