Slow transfer speed with Carbon Copy Cloner.

[Heyes]

I miss the old days when things worked and I knew how to fix 'em when they didn't.

So, I have my 2017 iMac (tiny 8gb memory) and Carbon Copy Cloner (7.0.4), hooked-up (USB 3) to a WD Elements.

I get transfer speeds of approx 3 mb/s when cloning my internal hd. It's the usual mix of relatively small file sizes (images, BB Edit files, etcetera).

And I get similar speeds when using CCC to clone files from that WD Elements to another WD Elements (file sizes typically 150mb to 1gb).

I realise speeds depend on many variables - and I don't know what speeds I've usually had.

I've only become aware of this after one of the WD Elements misbehaved and required a Disk Utility erase - and I'm now faced with cloning 5tb of files from one drive to another - with a suggested transfer time of many days.

Help appreciated, please and thanks.

 

[Heyes]

And perhaps someone can tell me why those two external drives have just spun-up when all I'm doing is browsing. There's nothing which should be using them right now.

 

[Bigwaff]

Do your WD Element enclosures have the latest firmware?

 

[eyoungren]

I miss the old days when things worked and I knew how to fix 'em when they didn't.

So, I have my 2017 iMac (tiny 8gb memory) and Carbon Copy Cloner (7.0.4), hooked-up (USB 3) to a WD Elements.

I get transfer speeds of approx 3 mb/s when cloning my internal hd. It's the usual mix of relatively small file sizes (images, BB Edit files, etcetera).

And I get similar speeds when using CCC to clone files from that WD Elements to another WD Elements (file sizes typically 150mb to 1gb).

I realise speeds depend on many variables - and I don't know what speeds I've usually had.

I've only become aware of this after one of the WD Elements misbehaved and required a Disk Utility erase - and I'm now faced with cloning 5tb of files from one drive to another - with a suggested transfer time of many days.

Help appreciated, please and thanks.

Might try turning off Safety Net. That's a per backup task setting.

 

[ignatius345]

So, I have my 2017 iMac (tiny 8gb memory) and Carbon Copy Cloner (7.0.4), hooked-up (USB 3) to a WD Elements.

I get transfer speeds of approx 3 mb/s when cloning my internal hd. It's the usual mix of relatively small file sizes (images, BB Edit files, etcetera).

And I get similar speeds when using CCC to clone files from that WD Elements to another WD Elements (file sizes typically 150mb to 1gb).

I'm assuming these WD drives are formatted APFS? Apparently APFS does not work very well with HDDs because it actually increases fragmentation (meaning more seek time from the data being physically fragmented across sectors of the drive platter). Gory details: https://eclecticlight.co/2019/10/19/should-you-enable-defragmentation-on-apfs-hard-drives/

Maybe you'd have better luck formatting them as HFS+, or dropping some cash and getting SSDs instead .

And perhaps someone can tell me why those two external drives have just spun-up when all I'm doing is browsing. There's nothing which should be using them right now.

Might be Spotlight indexing them.

 

[chabig]

It could also be because the iMac's USB ports only support 5Gbps transfer rate (according to to MacTracker).

 

[chabig]

It could also be because the iMac's USB ports only support 5Gbps transfer rate. In real world use, you shouldn't expect to see much more than 3Gbps (300 MB/s). If it's less than that, you could also have a cable problem.

 

[Heyes]

My thanks to all who've responded...

Do your WD Element enclosures have the latest firmware?

I assume so - one is just a few months old.

Might try turning off Safety Net. That's a per backup task setting.

Although it's an essential feature for ongoing backups, I could try it on the initial clone to the freshly-wiped drive.

I'm assuming these WD drives are formatted APFS? Apparently APFS does not work very well with HDDs because it actually increases fragmentation (meaning more seek time from the data being physically fragmented across sectors of the drive platter). Gory details: https://eclecticlight.co/2019/10/19/should-you-enable-defragmentation-on-apfs-hard-drives/

Maybe you'd have better luck formatting them as HFS+, or dropping some cash and getting SSDs instead .


Might be Spotlight indexing them.

Yes, they're APFS - HFS+ doesn't appear to be an option in Disk Utility.

For me, price has always been an issue with SSD and still is to some degree.
Pus, other than my daily clone, the contents of my external drives doesn't change much and so slower back-up time isn't an issue - but the time to restore 5gb after a disk erase *is*, and although I expect it to require days I don't recall things ever having been as slow as they currently are.

The external drives are excluded from Spotlight, so that shouldn't be why they suddenly spun-up.

It could also be because the iMac's USB ports only support 5Gbps transfer rate. In real world use, you shouldn't expect to see much more than 3Gbps (300 MB/s). If it's less than that, you could also have a cable problem.

It's 3mb/s I'm getting - around one-hundredth of your suggested speed.

And the cables are those supplied with the drives - no extensions or hubs are involved.

 

[ignatius345]

Yes, they're APFS - HFS+ doesn't appear to be an option in Disk Utility.

For me, price has always been an issue with SSD and still is to some degree.
Pus, other than my daily clone, the contents of my external drives doesn't change much and so slower back-up time isn't an issue - but the time to restore 5gb after a disk erase *is*, and although I expect it to require days I don't recall things ever having been as slow as they currently are.

I've experienced some very slow transfer speeds with Carbon Copy Cloner using HDDs as well, and I wasn't able to figure out exactly why either (sorry, that's of no help to you). If you're dealing with portable 2.5" drives, that could be a factor, according to this: https://support.bombich.com/hc/en-us/articles/20686495048215-Choosing-a-backup-drive

I've been moving to SSDs for most things, but it gets a bit costly once you start looking at larger capacities. Still, they've come down in price a lot over the past few years and if you happen to catch a decent one on sale, it could be worth it just to streamline things. I've found DiskPrices is a decent resource for shopping (though it is limited to Amazon).

 

[bombich]

Although it's [SafetyNet] an essential feature for ongoing backups, I could try it on the initial clone to the freshly-wiped drive.

SafetyNet isn't actually a part of the backup strategy, it's only a safety mechanism. I recommend disabling it any time the destination is dedicated to backing up the source. That said, it's not going to affect the performance of your backup.

ignatius345 is on the right track with the comment about slower HDDs, WD Element devices are on the slower end of the spectrum. Rotational HDDs, in general, are "alright", but I'd try to find one of the faster-spinning devices, especially if you have a bunch of smaller files. The file-size-distribution factor is huge too, I blogged about this one a while back (and this blog post also touches on "It's 3mb/s I'm getting - around one-hundredth of your suggested speed."):

File Copying Olympics: How File Size Impacts the Race for Performance Gold

If you're using a rotational disk for the source, APFS might not be a great choice for that volume. For larger files, I'd prefer APFS on any device. For a backup volume, I prefer APFS for any device. For a production source that has lots of small files, well, personally, I'd never use anything other than an SSD right now, but if an HDD is what you have, the legacy HFS+ format may be preferable until that device is obsolete.

Yes, they're APFS - HFS+ doesn't appear to be an option in Disk Utility.

Choose "Show All Devices" from Disk Utility's View menu, then select the parent container. If you select an already-APFS formatted volume, that volume exists inside of an APFS container, and that volume can't be reformatted as HFS+. But if you select the parent container or the whole parent device in the sidebar, HFS+ ("Mac OS Extended (Journaled)") will be a formatting option.

Mike (developer of CCC)

 

[Fishrrman]

Try different cables.

Try different USB ports (you may have done that already).

Try an SSD instead. It costs more, yes. But it's worth it.