I’m experiencing slow full restore speed when restoring from image backup created with Reflect v8.1.7336 in WinRE 11. My full backup from Windows took about 00:09:34 to 2TB Samsung T7 Shield using USB 3.2 Gen 2.  My C: drive is about 503GB used and the full backup image is about 433GB.  The full restore in WinRE 11 took about 00:32:30 from the same Samsung T7 Shield USB drive.  This drive has maximum 1050MB/s read and 1000MB/s write speeds.

Do you have RDR (Rapid Delta Restore) turned on for your restore?

Macrium is aware in certain instances, though hasn't elaborated on what those may be, that restores can be slower than they should be under 8.1.  An upcoming update said this should be addressed.

I turned off Rapid Delta Restore before starting a restore to see how long a full restore would take,

I did a new full disk backup under WinRE and it completed in 00:09:25.  I did a full disk restore under WinRE after disabling RDR and it completed in 00:28:13.  I did a verify image and it completed in 00:07:57.  Why is a full disk restore with RDR disabled taking so long, about three times longer than a full disk backup?

+x

 

Keith Weisshar - 4 February 2023 12:34 PM

I did a new full disk backup under WinRE and it completed in 00:09:25.  I did a full disk restore under WinRE after disabling RDR and it completed in 00:28:13.  I did a verify image and it completed in 00:07:57.  Why is a full disk restore with RDR disabled taking so long, about three times longer than a full disk backup?

@Keith Weisshar Your question implies that you don't understand Rapid Delta Restore. 

When RDR is disabled, the restore operation must read ALL blocks from the backup and write ALL blocks to the disk, even if the block that is on the disk is the same as that same block in the backup. It is guaranteed to take longer,, which you discovered.

It should still take about the same time as the full disk backup using normal compression and intelligent sector copy.  I'm using WD Black SN750 as the system drive and a Samsung T7 Shield as the backup target.  Both drives are NVMe based and the backup target is using USB 3.2 Gen 2 10Gbps to NVMe bridge.  The backup image is about 450gb because all of the Steam games installed on the system drive.  Restore times are slower on backup images taken with v8.1 than on backup images taken with v8.0.

Intelligent sector copy (which is active during a backup if enabled) will indeed make a backup complete more quickly because it will not save every cluster on the drive - just those in use.  

However, RDR (which is active during a restore if enabled) will prevent writing sectors that have not changed since the backup was made.  So if you do a backup, and then immediately restore with RDR enabled, VERY few clusters will need to be written back to the disk.  However if you do that same restore WITHOUT RDR then EVERY cluster in the backup will be written back to the drive.  Depending on the amount of data USED on your drive that could be a LOT of writes that were not needed when RDR was enabled.  That is why there is a major time difference in restore when RDR is used. Even with super fast NVMe drives it takes time to do a write.

Macrium Support and developers, Why does it take three times as long to do a full bare metal restore from the compressed backup created with Macrium Reflect v8.1 after creating a compressed full backup using Macrium Reflect v8.1 using the new backup engine?  I created a brand new compressed full backup of my WD SN750 2TB SSD drive containing 526GB of used space to my Samsung T7 Shield 2TB SSD using USB-C and this took almost 10 minutes.  I then wiped my WD SN750 SSD using ASUS Secure Erase utility from the UEFI BIOS Tools menu and then booted from the Macrium Rescue flash drive containing Windows RE 11 build 22621 and did a full bare metal restore back from the Samsung T7 Shield SSD to my secure erased WD SN750 SSD and this took over 30 minutes.  I have ASUS Maximus XI Hero Wi-Fi motherboard with Intel I9-9900K CPU.  The Samsung T7 Shield is connected directly to the USB-C port on the motherboard.  The Samsung T7 Shield was preformatted with exFAT from the factory.  I tried the LegacyBackup registry setting to use the old v8.0 backup engine and it makes new compressed full backups much slower and the transfer rate fluctuates between 600Mb/s to about 4.4Gb/s.  With the new v8.1 backup engine the transfer rate is over 6Gb/s.  I created a new uncompressed full backup and that took about 11 minutes.  When I restored from an uncompressed backup without RDR it took about 15 minutes unlike the 30 minutes when restoring from a compressed backup without RDR.  Even doing an immediate RDR after a compressed backup takes up to 2 minutes but doing an immediate RDR after an uncompressed backup takes about 30 seconds.

Repy from Macrium Reflect Team in another thread

I tried to add link but failed.

We have made some significant improvements to backup creation speeds in Macrium Reflect 8.1 and this required a slight change to the way backup data is stored in image files. We were aware that this image file format change could result in slower restore times, but our testing did not indicate that the change in speed was significant. However, with the benefit of user feedback and further testing, we have found some scenarios where the slow down is noticeable.

Our engineers have worked on this and they have now improved the Macrium Reflect 8.1 restore process so that it is now at least as fast as Macrium Reflect 8.0. That improvement is about to undergo testing in our QA Department and we expect to have an update available shortly.