Re: RAIDframe level 5 write performance(was: tstile lockup)

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Fri, Nov 02, 2012 at 06:02:01PM +0100, Edgar Fu? wrote:
> 
> Writing to that RAID's block device (raid2d) in 64k blocks gives me a dazzling
> troughput of 2.4MB/s and a dd mostly waiting in vnode.

Writing to the block device from userspace is not a good idea.  How is
performance through the filesystem?

The "block device" actually accesses the metadata cache.  It is not intended
for bulk writes and allocates memory in the kernel at every request.  It's
fine for what the filesystem needs it for, but not for what you're trying
to use it for.

Thor