Installed Sabnzbd+, downloading very slow

[Roel1963]

I am not sure where to post this, but as I am a beginner in Sheevaland, this seems the best place.

Just purchased a Sheevaplug Multiboot, with Debian Squeeze on an 8 GB SD card. At first I updated the Squeeze install, first on the NAND (which I would like to keep as a backup option for when the SD fails), later on the SD.

Everything worked smoothly and quite fast (from this point on I boot exclusively from the SD).

Then I installed a few apps, with Sabnzbd+ amongst them. Went to the configuration routine through ssh, attached a USB harddisk and started downloading. Then I got quite surprised about the download speed.

I have a fast internet connection (max 120 MBit/s) and a fast payserver for usenet (100 Mbit/s). My previous server (the one I replaced with my new Sheevaplug) could reach about 8.5 MB/s, which about equals 68 Mbit/s. The Sheevaplug however, starts the first seconds on 5.5 MB/s, then after about 5 seconds drops to about 1 MB/s, and from that point on maximises at about 2 MB/s, but can also drop to 10 kB/s and remain there for a looong time.

Now what can cause this very slow download time?

Extra info: the "incomplete" downloads are stored on the SD card that also holds the Debian install, the completed downloads are transferred to the USB (NTFS) harddisk. I also changed the destination of the incomplete downloads to that harddisk, but no change in download speed. At that point however, I saw when running top that mount.ntfs-3g ate about 25% of my processor usage.

Can there be a factor that slows down the downloadspeed? Is is the slow write speed of the SD card? The slow USB2 speed? Or is my Debian knowledge not enough and do I have to change some setting in the plug so that the speed will increase, with a little more plug knowledge?

Hope somebody will be able to fill me in on this...

[NewIT_James]

ntfs-3g does seems to consume high cpu and run slowly under certain circumstances, try formatting the usb disk to ext4 or ext3 and see if things improve.

[Roel1963]

ntfs-3g does seems to consume high cpu and run slowly under certain circumstances, try formatting the usb disk to ext4 or ext3 and see if things improve.

It was not an option for me to format this particular disk to ext4, so I attached another disk (ext4 formatted) to the plug, and created folders on that disk for download. Then I created symlinks on the SD (boot-)card and started downloading. Again, when starting, the download speed is incredible, but after just seconds it get slower, although not that much as when writing to the SD card or the NTFS harddisk.

I must say though, that I bought this disk in 2006 so it won't be the fastest, to today's standards. Can it really be that the write speed of harddisks is the big slowing down factor?
The NTFS disk is brand new, but this one needs to stay on NTFS (to attach to my media player).

Will a newer/faster disk really improve the download speed and therefore the overall performance?

[NewIT_James]

eSata is the best way to improve performance, roughly 60Mb/sec vs 20Mb/sec from a usb2 hard drive.

[Roel1963]

Hmmm unfortunately there is no eSata port on my plug....

Should have thought of this earlier.

Thanks anyway,
Roel