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Creation of zpools

A zpool must be created after configuring LUN for Solaris ZFS for optimum performance of ONTAP.

Solaris ZFS (Zettabyte File System) must be installed and configured carefully to allow good performance. Reliable ZFS performance requires a Solaris kernel patched against LUN alignment problems. The fix was introduced with patch 147440-19 in Solaris 10 and with SRU 10.5 for Solaris 11.

An incorrect zpool creation can result in serious performance degradation due to the I/O alignment. For optimum performance I/O must be aligned to a 4K boundary on the disk. The filesystems created on a zpool will use an effective block size that is controlled through a parameter called ashift, which can be viewed by running the command zdb -C.

The default vaule of ashift is 9, which means 2^9, or 512 bytes. For optimum performance, the ashiftvalue must be 12 (2^12=4K). This value is set at the time zpool is created and cannot be changed, which means that data in zpools with ashift greater than 12 must be copied to a newly created zpool.

After creating a zpool, verify the value of ashift before proceeding. If the value is not 12, the LUNs were not discovered correctly. Destroy the zpool, verify that all the steps shown in the relevant Host Utilities documentation were performed correctly and recreate the zpool.