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| Subject: | Re: slow sftp/scp access despite fast network |
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| Date: | Tue, 29 Nov 2005 13:22:52 -0500 |
On Tue, Nov 29, 2005 at 12:34:31AM +0000, Kris Harris wrote:
on the system of interest (i.e. sftp localhost), I get like 10Mb/s, so the server doesn't seem pooched
Hopefully you meant 10MB/s? 10Mb/s is about 1MB/s, which I think seems extraordinarily slow for transfers on the local machine... On my laptop I get about 6.5MB/s for a 20MB file. Which still seems rather slow to me, but it's more reasonable.
the computer is actually the head node of a small cluster and I get the results: node2 to to master(gutowsky) via sftp: starts at 200 KB/s and ends on a cumulative rate of 100 KB/s, which is acceptable I suppose node2 to master(gutowsky) via iperf: 4.49 Mbits/sec (560 KB/s ?)
These are on the same LAN? These numbers sound horrible. On a 100Mb/s LAN, you should be able to achieve speeds of at least 4-5 MB/s or so. Over my 802.11b network (11Mb/s) I can get speeds of up to about 700KB/s. With a 100Mb/s LAN and no encryption/compression, you should see speeds of around 8-9MB/s if your ethernet hardware doesn't suck (and isn't misconfigured).
(p.s., tried the usual net-problem charachters of switch, full/half duplex mode, and a different kernel module (but still 2.4 kernel))
Well, I definitely would have jumped on duplex being the issue... Did you check carefully the connections on both the switch and the local host to make sure there is no duplex mismatch? I've seen it happen fairly often that the switch autonegotiates to 100Mb/Full but the host autonegs to half duplex. Did you check the config on both ends of the connection (switch and host, for sender and receiver)? To check in Linux, you can use mii-tool or check the output of dmesg. If you're using GB ethernet, some distros may not have a version of mii-tool which reports the link status correctly. -- Derek D. Martin http://www.pizzashack.org/ GPG Key ID: 0x81CFE75D
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