[CentOS] Calling All FS Fanatics

Thu Oct 5 04:25:30 UTC 2006
Kirk Bocek <t004 at kbocek.com>


Feizhou wrote:
> For cases where you do not want to lose your data when you get a 
> blackout. If you do not have a battery power backup for your cache, you 
> will lose data that is in the cache that has not been committed to the 
> disks.

That's what I thought. But, jeez, that's *really* slow. I didn't have the 
patience to wait for a benchmark to finish but I'm guessing about 5MB/Sec 
writes. Not acceptable.

> Indexes directories are only useful for cases where there are thousands 
> of files in a directory and you want to access a single file (and you 
> know the name in advance) quickly.

That's also what I thought but wasn't sure.

> Are you using the no write cache flag with bonnie++? Otherwise you may 
> not get the same results from whatever it is that you are running.

I did *not* run bonnie++ with '-b'. I expect to use write caching in 
application, so that's what I want to benchmark.

> Run XFS without write caching and you should be safe. Are you creating 
> thousands of files?

The main stress on this system will be as a media server (mythtv and some 
other things.) So, no, files will be fewer and larger. Are you talking about 
write caching on the 3Ware? As I said, without it the system become 
unresponsive during large writes.