Mailing List Archive: ndmpcopy performance on F740

ndmpcopy performance on F740

Aug 9, 2002, 1:43 PM

Post #1 of 3 (1277 views)

What sort of throughput are people seeing between two F740s on
Fast Ethernet using ndmpcopy? I'm getting at best 4 megabytes per
second on the destination filer, with the CPU (from a "sysstat 1")
hovering above 95%. The source filer is still humming along at about
20% CPU (though difficult to tell, since there was other activity on
the source filer at the time). Doesn't seem that writes via NDMP are
very efficient on an F740 (6.1.2R1 on both ends). I'm starting to
think that putting a cheap FreeBSD Intel box between the two filers
doing copies over NFS will be faster (in fact, I'm pretty sure it will
be). Does it get better if I have parallel NDMP sessions going?
--
Brian Tao (BT300, taob@risc.org)
"Though this be madness, yet there is method in't"

Re: ndmpcopy performance on F740 [ In reply to ]

Joseph.Bishop at jpl

Aug 9, 2002, 2:40 PM

Post #2 of 3 (1239 views)

Permalink

Brian,

I have seen 6.5MBytes between an F760 and an F820.

Are you using UDP or TCP? And (ignorant question) is Fast ethernet Gigabit
or 100Mbit?

Joe

At 04:43 PM 8/9/2002 -0400, Brian Tao wrote:
> What sort of throughput are people seeing between two F740s on
>Fast Ethernet using ndmpcopy? I'm getting at best 4 megabytes per
>second on the destination filer, with the CPU (from a "sysstat 1")
>hovering above 95%. The source filer is still humming along at about
>20% CPU (though difficult to tell, since there was other activity on
>the source filer at the time). Doesn't seem that writes via NDMP are
>very efficient on an F740 (6.1.2R1 on both ends). I'm starting to
>think that putting a cheap FreeBSD Intel box between the two filers
>doing copies over NFS will be faster (in fact, I'm pretty sure it will
>be). Does it get better if I have parallel NDMP sessions going?
>--
>Brian Tao (BT300, taob@risc.org)
>"Though this be madness, yet there is method in't"

Re: ndmpcopy performance on F740 [ In reply to ]

taob at risc

Aug 9, 2002, 2:49 PM

Post #3 of 3 (1247 views)

Permalink

On Fri, 9 Aug 2002, Joseph Bishop wrote:
>
> I have seen 6.5MBytes between an F760 and an F820.

Ick.

> Are you using UDP or TCP?

This is using NDMP (not NFS), so I'm guessing it is a TCP
connection between the two filers.

> And (ignorant question) is Fast ethernet Gigabit or 100Mbit?

"Fast Ethernet" is 100 Mbps. I am able to write at over 10 MB/sec
via NFS to the very same filer, and the CPU isn't pegged near 100%, so
I'm guessing that the code path that handles NDMP writes in DOT isn't
nearly as efficient as the NFS code.
--
Brian Tao (BT300, taob@risc.org)
"Though this be madness, yet there is method in't"