On Wed, 2010-06-30 at 16:41 -0500, Nicolas Williams wrote:
> On Wed, Jun 30, 2010 at 01:35:31PM -0700, valrh...@gmail.com wrote:
> > Finally, for my purposes, it doesn't seem like a ZIL is necessary? I'm
> > the only user of the fileserver, so there probably won't be more than
> > two or three computers, maximum, accessing stuff (and writing stuff)
> > remotely.
>
> It depends on what you're doing.
>
> The perennial complaint about NFS is the synchronous open()/close()
> operations and the fact that archivers (tar, ...) will generally unpack
> archives in a single-threaded manner, which means all those synchronous
> ops punctuate the archiver's performance with pauses. This is a load
> type for which ZIL devices come in quite handy. If you write lots of
> small files often and in single-threaded ways _and_ want to guarantee
> you don't lose transactions, then you want a ZIL device. (The recent
> knob for controlling whether synchronous I/O gets done asynchronously
> would help you if you don't care about losing a few seconds worth of
> writes, assuming that feature makes it into any release of Solaris.)
Btw, that feature will be in the NexentaStor 3.0.4 release (which is
currently in late development/early QA, and should be out soon.)
Archivers are not the only thing that acts this way, btw. Databases,
and even something as benign as compiling a large software suite can
have similar implications where a fast slog device can help.
- Garrett
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