(SOLVED) Slow transfers

[pwatts]

Hi guys, I've tried all the usual tips and got no luck with speed issues. Some stats:

NAS4Free 10.2.0.2.2545 full install on 8GB flashdisk, 2GB swap
HP N36L mediaserver
1GB RAM
3x UFS HDD's & 1x NTFS (all a few years old and not supporting 4k sectors)
MTU size 1500
kernel tuning =on
CPU load always <50%
Memory usage even under load <30%; swap 11%
8% reserved space; drives freshly formatted & empty
Async & large file transfers enabled
All other performance guides followed

iperf = approx. 940Mbps
dd write =80MB/s
dd read = 105MB/s

SMB transfers of large (>1GB) files from a Windows host start at approx. 30MB/s and then drop to as low as 3MB/s. The larger the selection the slower it drops.
On the EXACT SAME setup (host, NAS, switch, cabling etc.) with a standard Ubuntu SMB host I got rates up to 80MB/s with similar transfers of the same files.

FTP performance is pretty much the same (guess this means it's not a SMB issue but wasn't sure where to post). This is not even a networking issue; doing an inter-drive copy from one drive to another of a single large file via the file manager also results in about 5MB/s!

Any assistance would be appreciated..

[pwatts]

Solved! Turns out it was insufficient RAM after all: despite the memory usage with 1GB being reasonably low; upgrading the RAM to 4GB fixed it all [rendering the swap file to 0%].

Transfers of large files are now >80MB/s, sustainable.

Seems even with non-ZFS systems (my setup just uses independent UFS & NTFS disks), more memory is still good.

The only remaining problem is inter-disk transfers with the File Manager, which are still only about 5MB/s.

[danzi]

Interesting, I now decomissioned the NL36 due to its low specs. Had it with 6 Gb RAM, with ZFS, 3x1.5 Tb disk and Samba was always slow.... now with a Poweredge T20, Xeon and 8 gig ram, it is also slow... so I think it must be the disks... they are quite old ones and are timely to replace anyways. I use both win and a Mac as a client

[pwatts]

Got to re-open this thread alas: somehow the transfer rates just dropped again, typical rate is in the 15MB/s range with all my UFS drives (no ZFS).

As before, networking is fine and during transfers the 5GB RAM utilization coasts at 20% and CPU load <10%, yet there's the typical signs of insufficient RAM of an initial speed burst that drops down. Any suggestions on what to inspect would be appreciated.