Comment 139 for bug 197762
Revision history for this message
| Neil Burlock (malone) wrote Re: file transfers on USB disk are very slow | #139 |
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0e1f616
(Get the code!)
I did have a long list of tests to attach here, but using dstat over the last couple of hours it appears that one of my drives that is connected via eSATA might be faulty. Until last week when I purchased a new 640GB I was using it (WD 500GB ext4) as my desktop drive and prior to that as my server drive.
I got the following from a transfer test of the 500GB WD drive:
2906193920 bytes (2.9 GB) copied, 62.6089 s, 46.4 MB/s
Which seems OK. However in my tests I've found that the eSATA slowdown is occurring only when reading from this particular drive, not when writing to it. I've tested several other WD drives, none of which are showing any slowdowns in reading or writing over eSATA. For now, eSATA is off the hook as being involved in this problem and I will dispose of the 500GB drive once I've got the rest of my data off it.
I'll begin testing USB and network transfers tomorrow. Potentially, this drive could have been involved in a lot of the performance problems since much of my copying is from flash to desktop to server and back in the reverse order. I'll need to do more testing.
In the meantime, I can't thank you enough Theodore Ts'o for explaining that performance test and dstat. I wish someone had suggested it a year ago...
I've attached a copy of the dstat from reading the 500GB drive for reference.