Time Machine Backup Insanely Slow

[clark9]

I just bought a new USB 3.0 2Tb G-Drive from the Apple Store to replace my aging USB 2 backup disk for Time Machine on my 4 yr old Macbook Pro (USB 2 bus). The old 500Gb USB disk was fine but I dropped it a couple of times and it is starting to act a little cranky so decided to upgrade to a larger and newer backup disk.

My new G-Drive came and instructions said to simply plug it in and start using it - which I did - and began to do the TimeMachine back.

Except the backup was running at about 100Mb per HOUR! and I had 200Gb to backup. I figured it would take on the order of 44 months to complete the initial backup.

I reinitialized the TimeMachine backup a few times and played with it for a few hours but just couldn't get the drive to run at a reasonable rate.

I then took the G-Drive to my newer work MacBook Air with a USB 3 bus and it setup and ran just fine.

There was nothing in the docs that said it wasn't USB 2 compatible. In fact, the USB 3 specs require the protocol to be backward compatible, and my USB 2 backup disk works just fine.

Any ideas before I ship the dumb thing back?

 

[ferrarr]

It did work with USB 2, so it is functioning properly, do you think a USB 2 drive will be faster? Do you know what speed the disk drive is inside the enclosure? 7200, 4200 rpm, this could be the difference in speed from your old USB 2 drive?

 

[clark9]

When I first setup the old drive it took about 4-6 hours to perform the initial backup. I thought that was a long time, but the weekly incremental only took a few minutes after that, so I didn't think much about it. The new drive was so insanely slow I thought it was broken until I hooked it up to my other laptop. Seriously, it was running at under 100Mb per HOUR. Not minute, or second. Per Hour. I calculated it would take at least 44 days for it to complete. BTW: I left it running for a full 18 hours to see what would happen and in that time had just barely backed up 1Gb of the 200Gb drive. When I plugged the old backup drive in it ran just fine. It's the weirdest thing.

The only thing that makes sense to me is that it is a USB 3 device running on a USB 2 machine. But my existing USB 2 drive works just fine, and USB 3 drives are supposed to auto-downgrade to USB 2 automatically, so it shouldn't be any slower than my old drive, even if the disk speed was half. This isn't about disk speed.

I can only assume that the USB 3 to USB 2 logic is messed up - which means it is firmware related. But I'm just guessing at this point.

 

[ferrarr]

True, but your existing Time Machine drive only has to update what is already on the drive, and not create a new backup. You could try to copy your existing Time Machine backup from the old drive onto the new drive, using your USB 3 Mac, and keeping all of your Time Machine on one drive and not on separate drives. Then, you can hold onto the "iffy" drive, or destroy it if you feel that there is no need to store it.

Also, as fas as drive speed goes, it could have an affect, if your old enclosure has a 7200 rpm drive and the new enclosure only has a 4200 rpm drive, the older drive will write the information faster than the newer drive, since they are both getting USB 2 speeds. Another thing to consider is, if one drive is USB powered and the other is a/c powered, this will affect read/write performance also.