Incremental Backup - First Full Backup Speed Normal, Subsequent Full Backup in Chain Slow
After installing Update 1, large backups using the TIBX format complete without an issue as advertised. The first full backup of my data drive (2TB) took about as long as a full backup took using TI 2019 (4hrs). The backup was configured to do another full backup after 10 incremental backups. The subsequent full backup took 15hrs. All my backup chains with the new format are exhibiting the same behavior. First full backup "fast"...subsequent backups slow.
I'm planning on removing TI 2020 and reinstalling TI 2019 until this issue and other issues get fixed. Right now I'm not confident that I'll be able to restore any of the backups I've made using TI 2020. My subscription runs out in seven days. If I renew, will I be able to continue using TI 2019? Or am I going to be forced to upgrade to TI 2020?
Allegato | Dimensione |
---|---|
Acronis TI 2020 Update 1 - First Backup.PNG | 6.58 KB |
Acronis TI 2020 Update 1 - Second Backup.PNG | 6.52 KB |


- Accedi per poter commentare

Thanks for the response Steve. When I initially posted I was fairly certain that the low backup speed for the second and subsequent full backups in the chain was a result of ATI 2020 throttling backup speeds. But after reading your post, I realized that somewhere between the time of the first and second full backups I had changed the USB3 port that the destination drive was plugged in to. So I figured I should do an additional test backup to rule out the port change as the issue. I have now confirmed that the change in the USB3 port was not the cause of the issue.
I deleted the full backup entirely for a task set to backup a drive containing 1TB of data. The source drive is an internal, secondary drive in my PC and the destination drive is a drive in a USB3 enclosure. I then created a new single chain incremental backup task configured to complete a new full backup after 10 incremental backups. The initial full backup took about 1.5 hours to complete. ATI reported the average backup speed to be around 1,000Mbps. I then manually ran the backup task 10times to force the next full backup. According to task manager, the write speed on the destination drive was approximately 300Mbps during the backup. When I went to bed shortly after starting the backup, ATI identified that the backup would take over 4hours to complete.
- Accedi per poter commentare

The only real factor that I can think of here is that there is extra 'work' to be done when making an incremental backup compared to a full one. ATI has to identify what data has changed since the prior backup rather than just include all the source data regardless.
The above said, I am not seeing any significant decrease in speed for my own incremental backup tasks but the volume of source data is much smaller than your 1TB. I do see lower speeds when doing differential backups.
One late thought, how much free space do you have available on your destination drive and is the drive fragmented at all, as both these aspects could influence the performance of the backup here?
- Accedi per poter commentare

I am posting a link to a resent thread about performance that may be of interest.
- Accedi per poter commentare

Thanks Enchantech. The issue described in the post you linked to seems to be the same as the one I am reporting about. I'll monitor that post for updates.
Before I abandon this thread, I just want to comment on the test that you ran and posted about in the other thread. I noticed that your full backup was very small (8.2GB), and that you did not experience subsequent full backups taking longer than the initial one. My recent experience with this issue is that smaller backups aren't impacted (or the impact is not as noticeable). I did a test backup of a drive with 250GB of data. The backup time for the first full backup in the chain and every subsequent full backup (after 5 incremental backups) took the same amount of time. I'm only seeing the increase in time for subsequent full backups on backup tasks for my 1TB and 2TB data drives. The destination drive is a freshly formatted 6TB WD Black drive in a USB3 enclosure. So fragmentation and low disk space should not be factors for determining write speeds.
The other thing I noticed in tests last night is that the number of incremental backups between full backups seems to impact the backup time for subsequent full backups. On one test I set the backup of my 1TB drive to complete a full backup after two incremental backups. The first backup took an hour and half as expected. The second full backup took just over four hours. The previous backup task I had set up for the same drive did a full backup after 10 incremental backups. Every subsequent full back completed after the initial one took 12 to 14 hours to complete.
- Accedi per poter commentare

It's interesting that this doesn't scale linearly. I would expect the effect to show up on a 250GB but to a lesser degree. I wonder if there is a change in processing once a certain size is reached.
- Accedi per poter commentare