disk to disk backup transfer rate

zombine210

zombine210

New Member
I'm trying to figure out why this operation is so slow in windows backup util.

hardware:
32 bit pci bus @ 133 MB/s
promise sata300 tx4 controller card @ 3 Gb/s
2x 1TB seagate barracudas sata hdds @ 3 Gb/s

the backup copied 210 GB in 8 hrs, or 26.25GB/hr.

26.25 GB/h x (1hr/60min) x (1min/60sec) x (1024MB/1GB) = 7.47 MB/s

doesn't that seem slow?
 
3Gb/s is simply how fast the SATA technology is capable of transferring data. In reality you're limited by how fast your hard drive can read and write data which is much slower.
 
PohTayToez said:
3Gb/s is simply how fast the SATA technology is capable of transferring data. In reality you're limited by how fast your hard drive can read and write data which is much slower.
Click to expand...

i understand the theoretical transfer rate for is about 300 MB/s. shouldn't real transfer rate be closer to 30~40 MB/s? that's what i've read others are getting online.
 
I don't use the Windows backup utility but the speed is very dependent on exactly what you are doing. My comments below are generic:

1. If it's an incremental backup then the utility would first have to scan the drive and the existing backup for all changed files.

2. If you want the backup to be checked for integrity, it may take nearly twice the time of a blind backup.

3. If you have a lot of small files it will take much longer than a few large files.

4. Backup up to the same drive will be slower than to another drive

You should watch the backup and see what is going on. Most backup utilities show what stage they are at and which files are currently being transferred.

Your speed sounds slow to me considering the hardware. If you are doing a simple backup (straight copy of the files) the time should be similar to dumping the files manually. To test, create a temp folder on the backup drive and copy a bunch of folders from the operating drive into that folder just using Explorer. Check the overall data rate.
 
Nanobyte said:
I don't use the Windows backup utility but the speed is very dependent on exactly what you are doing. My comments below are generic:

1. If it's an incremental backup then the utility would first have to scan the drive and the existing backup for all changed files.

2. If you want the backup to be checked for integrity, it may take nearly twice the time of a blind backup.

3. If you have a lot of small files it will take much longer than a few large files.

4. Backup up to the same drive will be slower than to another drive

You should watch the backup and see what is going on. Most backup utilities show what stage they are at and which files are currently being transferred.

Your speed sounds slow to me considering the hardware. If you are doing a simple backup (straight copy of the files) the time should be similar to dumping the files manually. To test, create a temp folder on the backup drive and copy a bunch of folders from the operating drive into that folder just using Explorer. Check the overall data rate.
Click to expand...


1. this was the initial full backup.
2. no option selected to check data.
3. user files contain office docs as well as photos and music.
4. copying from one disk to another on the same controller.

i didn't sit there for 8 hrs obviously, but i watched it for a few minutes, it seemed to just be copying files over.

this speed is suspiciously similar to what you would get over 100Mbit LAN.
i measured copying a 500 MB iso to another computer and it was very close to the minute.

i'm gonna try just copying the files over manually, but i really wanted to have windows do this automatically.
 
my other backup ran tonight; it looks like it went a lot faster. it's two jobs per backup:
20.2 GB/ 1178 sec x (1024 MB/ 1GB) = 17.6 MB/sec
&
5.9 GB/ 404 sec x (1024 MB / 1 GB) = 14.95 MB/sec.

that's still slow but faster than the first backup, here's the final numbers:
39.2 GB / 2844 sec = 14.11 MB/sec.
&
244.5 GB / 43909 sec = 5.7 MB/sec.

it's that second job in the first backup that went really really slow...
that's my bro's files and our media folder with photos, videos & music.
 
copied 5.9 GB in about 5 minutes. don't have a stop watch, so can't count seconds. that's about 20 MB/sec not bad... still think it could be faster.
 
zombine210 said:
copied 5.9 GB in about 5 minutes......
Click to expand...
72GB/hr. Assuming that's direct copying it's a heck of a lot quicker than the utility. I found an MS article from a few years back which said that the utility was designed for up to 200GB. Above that, it becomes slow and a disk image would be quicker. I don't know whether that applies to your version of Windows. Not everyone wants a disk image. Incremental backup is more useful to most and incremental keeping old file versions too is ideal imo.

I can't advise on speeding things up. I do my full backups overnight so don't care about speed - incrementals don't take that long.
 
Well, a disk image is always going to be much faster except for small file transfers. I use Acronis True Image and I can clone 40 to 80GB in about 5-10 minutes.
 
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