For those of you running the Seagate 2TB LP drives.  What are your read rates?  I'm having real trouble getting over 25Mb/sec.  All I have in my unRAID array are these drives.

 

To test the "read" rates of the disks themselves, type

hdparm -tT /dev/sdX

where sdX = the disk device.

 

Or

you can test using a specific file. 

dd if=/mnt/disk1/directory/filename of=/dev/null bs=8k

Just be sure to use a large enough file so a subsequent test does not read it from cache.

 

The "dd" command will print timing and speed statistics.

 

Also.. 25Mb per second is NOT 25MB per second.  Which are you getting? Bytes per second, or bits per second.

 

 

 

 

/dev/sdh:

Timing cached reads:  2598 MB in  2.00 seconds = 1299.41 MB/sec

Timing buffered disk reads:  324 MB in  3.00 seconds = 107.87 MB/sec

 

For those of you running the Seagate 2TB LP drives.  What are your read rates?  I'm having real trouble getting over 25Mb/sec.  All I have in my unRAID array are these drives.

 

To test the "read" rates of the disks themselves, type

hdparm -tT /dev/sdX

where sdX = the disk device.

 

Or

you can test using a specific file.  

dd if=/mnt/disk1/directory/filename of=/dev/null bs=8k

Just be sure to use a large enough file so a subsequent test does not read it from cache.

 

I have just replaced all my 7200.11 drives with 2TB LP drives.  Using the dd method I'm seeing all sorts of speeds that range from 37MB/s to 109MB/s.  I suspect that the speeds reflect where on the platter the specific file is located.  Faster towards the outer tracks.

 

All read tests were using GB sized iso files, except one test was with a 74GB file.  

 

disk1:

69.4GB read 1093 seconds, 68.4 MB/s.

 

disk2:

928MB read 19.6 seconds, 47 MB/s.

4.6GB read 42 seconds, 109 MB/s.

3.5GB read 87 seconds, 40 MB/s

4.7GB read 133 seconds, 35.5 MB/s

 

disk3:

5.3GB read 13 seconds, 406 MB/s.

5.8gb read 55 seconds, 106 MB/s.

4.7GB read 111 seconds, 42 MB/s.

 

disk4:

4.3GB read 114.4 seconds, 37.4 MB/s

69.4 read 666.4 seconds, 112 MB/s

 

 

Write speed test:

I also copied the 69.4GB file from disk1 to disk4 using cp:  69.4GB (74,755,666,784) written 33m54s (2034s) = 36.7 MB/s