VMware vSphere • Re: Poor restore performance when restoring in AllFlash environment

Hi Eric,

I'll try to run your test today or tomorrow. However, there are some new findings:

If I set the virtual disk type to thick (eager zeroed) during the restore, the data rate increases significantly during the restore. Interestingly, there's no longer any difference whether the backup was created with a 1 MB or 4 MB block size. There was a big difference when restoring with a lazy zeroed disk. Let me summarize briefly:

Lazy zeroed:
1MB blocksize: Restoring Hard Disk 1 (100 GB): 28.2 GB restored at 98 MB/s [san]
4MB blocksize: Restoring Hard Disk 1 (100 GB): 28.8 GB restored at 152 MB/s [san]

Eager zeroed:
1MB blocksize: Restoring Hard Disk 1 (100 GB): 28.2 GB restored at 260 MB/s [san]
4MB blocksize: Restoring Hard Disk 1 (100 GB): 28.8 GB restored at 254 MB/s [san]

I find this exciting. It's still not the expected performance, but it's significantly faster.

Statistics: Posted by MirkoKiel123 — Jun 30, 2025 6:21 am

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