Speed

[MvL]

Hi,

 

I did some experimenting with unRAID, and i must say i'm very positive about this product. I have a question my transfer speeds when coping from my client to my unRAID tower is about 10MB/sec. I find this slow. I read in the forum that transfer speeds are normally higher about 30 - 40 MB/sec. I have a Cat6a network (10Gbps), but the router is Gigabit speed. I have two 1 TB Green power western  digitals (5400rpm), is this the reason transfer speed are slow? I also have a Hitachi 1TB drive (7200rpm), is this the best disc to make this the parity disc?

[BRiT]

No, it's not the drives at fault. I have 3 2TB 5400 RPM Green Drives in my array and I get over 30 MB/s transfers on my Gigabit network.

[MvL]

Fast reply, thanks BRiT.

 

I just realized with my Windows Home Server (WHS is history) i'll get transfer rates about 70-80 MB/sec. Hardware issue?

 

 

 

No, it's not the drives at fault. I have 3 2TB 5400 RPM Green Drives in my array and I get over 30 MB/s transfers on my Gigabit network.

[MvL]

Great wiki.

 

Found one answer:

 

Do 'green' drives work with unRAID?

 

Yes they do, and work well, usually creating savings in power costs. Note that although they can be used for both parity and data drives, for best write performance, select a faster drive for the parity drive.

A good thread about Western Digital 'Green' drives: http://lime-technology.com/forum/index.php?topic=1540.0

 

So i replace the parity drive for a 7200RPM Hitachi. The array is now syncing!

[MvL]

I think i also found the problem of the slow transfer speeds. I did:

 

dsmeg | grep eth0

 

output

 

eth0: rtl8168b/8111b.........
r8169: eth0:link up

 

and

 

lsmod

 

output:

 

r8169

 

So the wrong driver is loaded. I have a Realtek 8168b/8111b its is a integrated NIC on a Gigabyte motherboard. Can i replace this driver?

 

[MvL]

My parity drive is now the hitachi 7200RPM 1TB, and i add the two western digitals 1 TB for storage. The system is running smoothly. I even can stream 1080P DTS-HD movies to my Tvix 6600N without stuttering. With Windows Home Server this was a no go. Also the transfer speed from client to tower box improved. Its about 15-20 MB/sec. Still a bit slow...

[MvL]

Did a lot of reading in this forum. Lots of information in this forum. I understand 20MB/sec is a normal speed for unRAID (client ---> unRAID box). I'm correct? What speed do i get when using a cache drive (gigabit network). About 60-90MB/sec?

[BRiT]

That depends on which version you're using. Under the 4.5.4 (and recent), an average speed on Gigabit network with an average CPU server is 30-40 MB/s when writing to the array directly. With a fast cache disk, you could see 60-90 MB/sec. At that rate, the limitation is more likely to be on the sending side as well.

[bubbaQ]

When you write 1GB to unRAID, your data and parity drive has to:

 

    read 1GB, then write 1GB back to the same spot on the drive

 

If you have a drive that sustained reads at 85MB/s and sustained writes at 70MB/sec.

 

That takes 11.8 seconds to read and 14.3 seconds to write.  That's 26.1 seconds to write 1GB, or 38 MB/sec.  That is a hard limit -- the theoretical maximum write speed you can get with that disk in unRAID.

 

For various reasons, you can't get the theoretical max.  And as you use the drive and move away from the fast outer cylinders, the drive read and write speed gets much slower.

 

The Linux kernel had some recent changes that gave significant disk I/O performance improvements, and those are in the latest releases of unRAID, so be sure to upgrade to 4.5.4 or later.

 

[MvL]

Thanks for the reply BRiT and bubbaQ.

 

That explains a lot.

 

I have a gigabit network. My unRAID box use the following hardware, and using version 4.5.4.

 

 

cpu: e7200

motherboard: Gigabyte GA-G33M-DS2R (Realtek RTL8111B LAN Controller).

harddrive: 1x Hitachi 7200RPM 1TB SATA model (parity drive), 2x Western Digital 5400RPM 1TB SATA model.

 

 

When i write to the array directly speeds are about 20MB/sec. Using windows7 file explorer. So transfer speed are a little slow. Is this because i have the wrong driver for my NIC?

 

[vca]

Thanks for the reply BRiT and bubbaQ.

 

That explains a lot.

 

I have a gigabit network. My unRAID box use the following hardware, and using version 4.5.4.

 

 

cpu: e7200

motherboard: Gigabyte GA-G33M-DS2R (Realtek RTL8111B LAN Controller).

harddrive: 1x Hitachi 7200RPM 1TB SATA model (parity drive), 2x Western Digital 5400RPM 1TB SATA model.

 

 

When i write to the array directly speeds are about 20MB/sec. Using windows7 file explorer. So transfer speed are a little slow. Is this because i have the wrong driver for my NIC?

 

 

I'm using all WD Green Drives (i.e. 5400 RPM) including the parity drive and get up to 24MB/s writes when writing from a Windows XP machine to the unRAID box, so 20MB/s is not too bad.  If the problem is to do with the network it could also be your cables or switch, though usually problems would cause your network speeds to drop back to 100Mb/s and this would throttle file transfers down to the 7-10MB/s range.  So I wouldn't waste much time on the network.

 

Another possibility is that one or more of your drives is being configured to run at a reduced SATA speed, the system log file will show this.

 

Regards,

 

Stephen

[MvL]

Hi vca,

 

My network is not causing the troubles. All connections are tested with a Fluke DTX CableAnalyzer.

 

Yesterday i copied some movies to me unRAID box, and the speeds where now about 20-25MB/sec. So nothing to wurry about i understand.

 

When i want to check my log file where i have to look for? I want to test unRAID for a couple of months when satisfied i buy a licence. Then i want to use a cache drive. I very positive about this software.

 

Has Lime-technology ever considered to support a trial period of the pro version? So i can test the pro features...

[vca]

Hi vca,

 

My network is not causing the troubles. All connections are tested with a Fluke DTX CableAnalyzer.

 

Yesterday i copied some movies to me unRAID box, and the speeds where now about 20-25MB/sec. So nothing to wurry about i understand.

 

Yes that sounds fine.  If you want to make it go slower just install an old PATA drive, that'll slow things down to something like 10MB/s (or less if you use an old 20G unit!).

 

When i want to check my log file where i have to look for?

 

There are a few ways, see this help page:

 

http://lime-technology.com/wiki/index.php?title=Viewing_the_System_Log

 

and if you install the unMENU package its easier to get to.

 

Regards,

 

Stephen

 

[MvL]

There are a few ways, see this help page:

 

http://lime-technology.com/wiki/index.php?title=Viewing_the_System_Log

 

and if you install the unMENU package its easier to get to.

 

Hi,

 

Hmm, have to checkout unMENU. Thanks for the tip!

 

Yesterday i used Putty to login onto my unRAID box. I tried before, but used SSH. Yesterday i read that i have to use TELNET, and it works great.

[Kaygee]

20-25MB/s is about right, copying to a protected array.

 

[MvL]

20-25MB/s is about right, copying to a protected array.

 

 

Thanks for confirming Kaygee.