I am trying to transfer a number of large (10's of GB up to 100's of GB) files to an HP DL380 host, running vsftpd on a 10 GigE network / LAN. The transfer initially starts out fast, i.e. 45-60 MB/sec or roughly the speed of the disks. After several minutes (usually about 10-12) the transfer rate drops to a trickle (250 KB/sec or so). We do this sort of thing all the time to other servers, so it seems there is something with the server itself or perhaps a firewall between the client / server.
I am trying to troubleshoot this issue, and why our rates would suddenly and dramatically change. It does not seem to have anything to do with load on the network or the client/server. We suspected it had something to do with PASSIVE/ACTIVE mode, but that hasn't played out (transfers are in PASSIVE mode).
I'm hoping someone out there has seen something similar, i.e. a dramatic drop off in FTP performance. Some network parameter perhaps? A config item in vsftpd?
Anyway, any suggestions appreciated.
Best Answer
Before zeroing in on the FTP aspect, you should perform some synthetic tests to rule out other causes. (I've assumed both the client and the server are Linux since you are running vsftpd.)
cat /proc/net/dev
on the client and server to see if there are any errors or dropped packets.cat /proc/net/dev
.dd
to read from/dev/zero
and write to a local file on the target filesystem. Monitor throughput withiostat
.If any of the above tests show problems, you should have a clue about where to look next. Otherwise, look into the FTP side:
top
. If there's a memory leak something may be swapping and slowing everything down.