UFS is not unmap aware so it won't be able to issue an unmap command.
These features were back ported to Solaris 10 (patches 150400-07 and 150401-07).
If you want to use these features in Solaris 10 then you would need to use with ZFS file systems.
We had some had a performance bug associated with the unmap feature so it is disabled by
default. You would just need to enable it.
Thanks a lot for you answer. I found in 150400-07 that: "15613053 implement ATA TRIM, SCSI Write Same / UNMAP , Thin Reclamation", nothing about UFS/ZFS.
How to enable TRIM/UNMAP feature for UFS-based Solaris 10? I want to test performance if this solution.
Or is it totally impossible to enable TRIM for UFS?
Solaris installation in my case will use a metadevice-based RAID1 for root disk. Are any troubles possible to use TRIM for metadevices RAID1?
I talked to the engineer who implemented the SCSI UNMAP support and he says that UFS doesn't support this feature.
See the steps below for enabling the SCSI UNMAP support but you will need to use ZFS.
1. Enable this feature by adding the following entries to the
2. Reboot the system.
A 1MB (0x100000) size is recommended so that smaller areas are not
You might see a performance penalty when this feature is enabled, so it should be tested in their environment.