[OmniOS-discuss] Status of TRIM support?

[Dan Swartzendruber]

> The 840 Pro doesn't have a super cap, but it does properly honor cache
> flushes which ZFS will do on a log device.   This drastically reduces it's
> write performance and makes it a poor choice for a log device.
>
> Intel has several SATA SSDs with proper super-cap protected caches that
> make good log devices.   They are nothing like a ZeusRAM, but will protect
> your transactions.
>
> Keep in mind vSphere is a 100% sync write NFS client. If the log device
> doesn't perform well, neither will vSphere.

Correct.  Hence the sucky numbers with sync=standard and on-pool ZIL :)

> If you trust your backups I would stick to ZIL disabled.   If you want to
> do HA, you need to look at an all SAS solution, which is not cheap.

This is what I am not 100% clear on.  My JBOD has dual inputs, but it
isn't (yet) clear to me if the two input connectors talk to the separate
SAS ports on the SAS drives, or both go to the primary port, and rely on
the hosts co-operating (I've googled a lot for this kind of info, and come
up dry).  I need to move one of the server motherboards to a new case, at
which point I will plug that 2nd HBA into the 2nd SAS IN port on the JBOD
- if they see different WWNs, they are talking to the separate ports on
the SAS drives, else they are both talking to the primary port, in which
case it would seem I could use a SATA SDD for ZIL, no?