I am in the process of moving 750GB of data from an old server to a new one. I originally tried using a crossover cable between the two machines but after running for 24 hours it had only transferred 70GB and I really don't want to have to take a week to do this.

I picked up a 1TB external USB hard drive in hopes of copying the data to that external drive and then moving that drive to the new server and copying the data from there.

I first connected the drive to a Windows XP machine and copied 11GB of data over to it. That took about 9 minutes. I determined that meant it would transfer about 60GB in an hour so if I started the copying process (I was using star with the -copy option if that matters) before leaving around 8:00 or so tomorrow morning the data should be transferred to the external drive and then I could connect it to the new server and begin uploading and then just copy any files that changed Tuesday night and be ready to take the new server live on Wednesday.

Unfortunately, when I connected the external drive to the Linux machine the results I obtained were much different. Using the hdparm -Tt option it is saying that it can read from the drive at 26.6MB/s. Assuming that is sustained it seemed like that should mean a nominal 60GB per hour transfer rate as I had determined when I tested the drive in XP. But when I started actually copying files the actual throughput on Linux was more like 3.3MB/s. I was testing 60 second increments and it was copying about 200MB every minute. I decided that the 12GB/hour rate was a lot worse than I wanted but about 50% better than what I was getting through the 100BaseT connection.

Does anyone have any ideas why this drive would run so much slower under Linux than XP?

I verified that the port it is connected to is a USB 2.0 port. This is what my /proc/bus/usb/devices entry contains about it:

T: Bus=04 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 3 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0d49 ProdID=7310 Rev= 1.25
S: Manufacturer=Maxtor
S: Product=OneTouch
S: SerialNumber=2HA4CCEB
C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr= 2mA
I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms

I also reformatted the drive to the XFS file system when I attached it to the Linux system and mounted it with the noatime option.

I am trying to copy over 750GB of data contained in about 2.5 million files. If it maintains its current rate it is going to take about 3 days. Hopefully the other server will not have the same issues with the drive and the data can be uploaded much faster.

Use SATA instead of USB. USB has always been slow. For me it is always been unreliable too, so it is not good for back ups. If you are copying from a GUI program, the performance will be very poor because it have to do a lot of updating and calculations to post the status.

If you get 26 MB per second in hdparm. It will most likely be half that with a file system. If you want a good benchmark, iozone is better.

I suggest connect the server together with the back up system using a separate 1 Gb NIC. A RAID-5 or RAID-6 may have to be used on the back up system to load the 1 Gb NIC and to cut down time.