Hi Bob and all,
So this sounds like we need to wait for someone to come with a definite
answer.
I've received some helpful information on this:
> Byte 17 is for "Ignore Force Unit Access".
> Byte 18 is for Ignore Disable Write Cache.
> Byte 21 is for Ignore Cache Sync.
>
> Change ALL settings to 1 to make sure all "bad" commands are ignored.
>
> Byte 21 is the most important one, the other two settings are for safety.
note: Personally, I think that talking about "safety" in this context can be a
little misleading, my understanding of what is meant here is to make sure that
the cache is always being used - which can mean the contrary to (data) safety
(I've just learned from wikipedia that "Force Unit Access" means to bypass any
read cache).
> Newer Solaris (05/08 and higher) should automatically detect a Sun Storage
> array and should handle the ICS correctly without any modification be reading
> the Sync-NV bit.
Can anyone make a definite statement on this?
My understanding is that it does NOT yet work as it should, see also:
http://www.opensolaris.org/jive/thread.jspa?messageID=245256
In other words, my understanding is that we DO still need the Hacks on the
61xx/25xx or zfs:zfs_nocacheflush=1 for optimal performance.
Regarding my bonus question: I haven't found yet a definite answer if there is a
way to read the currently active controller setting. I still assume that the
nvsram settings which can be read with
service -d <arrayname> -c read -q nvsram region=0xf2 host=0x00
do not necessarily reflect the current configuration and that the only way to
make sure the controller is running with that configuration is to reset it.
Nils
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
