This might be a better question for the Illumos group, so please let me know.
I have a zvol for a KVM instance which I felt was taking up too much space. After doing a little research, I stumbled upon http://support.freenas.org/ticket/2383 and repeated the test on my machine. I'm running a RAIDZ2 pool with eight "advanced format" 4k sector drives. I created the pool with ashift=12 with this in mind. root@hostname:~# zfs create -V 20g -o volblocksize=32k storage/testbed/32k root@hostname:~# zfs create -V 20g -o volblocksize=8k storage/testbed/8k root@hostname:~# dd if=/dev/zero of=/dev/zvol/rdsk/storage/testbed/32k bs=1048576 count=20400 20400+0 records in 20400+0 records out 21390950400 bytes (21 GB) copied, 493.836 s, 43.3 MB/s root@hostname:~# dd if=/dev/zero of=/dev/zvol/rdsk/storage/testbed/8k bs=1048576 count=20400 20400+0 records in 20400+0 records out 21390950400 bytes (21 GB) copied, 548.916 s, 39.0 MB/s root@hostname:~# zfs list | grep testbed storage/testbed 64.2G 5.79T 307K /storage/testbed storage/testbed/32k 21.3G 5.79T 21.3G - storage/testbed/8k 42.8G 5.79T 42.8G - The 8k blocksize zvol takes up twice the space of the 32k blocksize zvol. As 8k is the default, this must be affecting others... --jason _______________________________________________ OpenIndiana-discuss mailing list [email protected] http://openindiana.org/mailman/listinfo/openindiana-discuss
