On Tue, Sep 16, 2008 at 2:24 PM, Nicholas Bernstein nick@nicholasbernstein.com wrote:
You're moving from trad vols to flex vols? Did you perhaps expand the traditional volume by adding a disk or two when you started running out of space, as opposed to pre-allocating all your disks?
I'm sure that this has happened over time as we've added capacity to the environment and upgraded from OnTap 6.x to 7.x.
You could be doing your reads from all your disks concurrently on one filer and one or two on the other.
This makes sense and comparing filers who are impacted versus those who are not, I'd bet this is the case. - I've noticed that for the impacted filers I'll get lousy performance for the first, say, 150g of a ndmpcopy (like <2g/hr on average) and more acceptable performance (like 9g/hr on average) after 150g has been transferred. - I've noticed that ndmpcopy between trad and flex vols (where the trad vol is the same size but with far less inodes used), the performance of ndmpcopy is approximately equal to what I've seen on our other files (18-20g/hr). I make note of this since one of the other responders in this thread mentioned inode usage/directory size and I suspect that this is one of two things that we're bumping up against here.
Also, is this filer being used for other tasks while the ndmp is occurring?
No, thankfully.