Performance problem when downloading

[jarlew]

Hello.

 

I'm using uTorrent to download files to the pool (mediaserver), but I have a problem after i formatted my server.

 

Win7 x64 pro

2x LSI SAS 9220-8i (IT-mode)

12x WD green 4TB (WD40EZRX)

 

Before I formatted, there was no problem at all, but now the cache in uTorrent (set to 256MB) will fill, and it will struggle to push the parts to disk/pool. When I download to a disk outside of the pool, there is no problem.

 

The settings in uTorrent is exactly as it was when it was working (used backup settings).

 

Also, if I give a pooled drive a drive letter (or mount to folder), and download directly to the root of that drive, the same thing happens.

 

It will take about 10-15 minutes to empty the 256mb large cache. Before I formatted my server, I could download with sustained 145mbit/s for several hours directly to the pool.

 

If I copy files from a non-pooled drive to the pool, the performance is as expected (up to 80MB/s). There is no problem with reads from the pool as I can see, only pushing smaller chunks of files from RAM to pool.

 

I'm not saying that this is a problem with the pool-software, but the problem only appears when downloading to it.

 

Another interesting thing is that when uTorrent tries to empty the cache (after download is stopped), and nothing more is added to it, I can see that there are activity on the disk in Stablebit Scanner (but nothing in DrivePool). And resource monitor confirms that utorrent.exe is writing to the disk (~30MB/s for several minutes).

 

There is no settings for the SAS-controllers when in IT-mode (IT: each disk separate, no RAID options).

 

Is there any settings to DrivePool/Scanner that can be changed?

Is there any setting to Windows that could impact this?

Any other suggestions?

 

The pictures below are from uTorrent disk logger. As you can see the dark green line fills the cache, and there is no write to disk.

 

(There is other strange things in windows also. When trying to create or rename a folder, explorer throws an error saying the item could not be found...)

[Christopher (Drashna)]

Are you preallocating files in uTorrent?  If not, you may want to do so, as this *may* help.

 

Otherwise: 

What version of StableBit DrivePool are you using specifically?

And could you enable file system logging and reproduce the issue. 

http://wiki.covecube.com/StableBit_DrivePool_2.x_Log_Collection

[jarlew]

Hello again. Sorry for late reply, I was sent to work in Egypt suddenly...

 

However, I have now enabled pre-allocate all files in uTorrent. This helped very much! Very strange that uTorrent worked without this before formatting my server, but not after. Anyway, this is just great.

 

Not sure where to find the version inside the program itself, but the exe-files in the programfiles-folder has version 2.1.1.561.

 

I have the ability to set the disk cache to 1024MB, this will make uTorrent write to disk more intermittent with larger chunks of data. What is best for the disk? Smaller, continuously write, or larger more intermittent writes?

 

Another question that fits better in the uTorrent support forums:

With pre-allocation enabled, the filesize of the complete torrent will be allocated on disk when loading the torrent. But what if only download half of the files the torrent includes. Will the other half (that I don't download) still be allocated, and not usable for other files?

 

edit:

I just had another strange thing... I have Scanner automatically scan my drives every month. Today is the day for some of the disks. When downloading to a disk that is currently scanning, the scan will not stop. uTorrent cache (1024MB now) will fill, and the torrent will fail with message (drive not ready, or something like that).

If I press stop in Scanner, and then start in uTorrent again, everything is fine.

I have set the throttle interference to medium sensitivity.

Option for not to interfere with disks on the same controller is checked.

Once I stop the scanning, uTorrent starts to dumps its cache (if scanner is stopped before torrent fails).

 

edit2:

Well, it happened again. This time its a TV-series (multiple files). I reduced the cache to 256MB again. Waited until it cleared (took a long time), started the log, started to download, cache fills, logged for another 10 seconds. Uploaded to your BOX. Please let me know if you need more.

I don't know if the log files got anything, the zip is only 1MB. 

 

edit3:

It's working as it should again now... I'll do some more testing.

[Christopher (Drashna)]

Preallocation is better for a number of reasons, and performance is definitely one of them.

 

As for the size, that really depends on a number of factors, include the underlying disks in the pool, the size of the torrent and the files in it.  So I really can't give you a good answer there, sorry. 

But if you ahve a higher speed, larger chunks may be better. And large files? Larger chunks, again. 

 

 

And if you only download some of the files, then yes, it will use the space and won't be available for other files. There isn't exactly a good solution for this... and it's why I use a dedicated disk/pool for torrents. 

 

 

 

As for the activity, that is ... rather odd.  In the throttling options, are you using the "Background I/O" option? If not, that could definitely contribute to the issue.  

Otherwise, try a "high sensitivity", as the activity from the torrent may not be high enough to trigger the throttling behavior (depending on the speeds that you get).