Backup size Full vs Delta
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Hi there,
I'm wondering about backup size differences between Full backup and Delta backup.
I've backed up the same 8 VMs:
- Full backup with zstd compression = 259 GB on backup repository
- Delta backup (only the first, so is a full backup) = 590 GB on backup repository
I think I've read on some other thread that delta backup always use compression (and that's why you cannot choose compression on the job parameters). Is it really the case?
Thanks
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A few questions, what is your retention set on the Delta job (how many copies are you keeping)?
Delta is going to create an initial full, and then only take the difference between that latest and the occurring backup to finalize the job.
If your retention is set to 6 or 7, that amount of space being consumed isn't unrealistic (590GB).
IDK if delta's technically compress of not off hand.
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@DustinB
My retention is set to 14, but as mentioned in the initial post, the size of the delta backup I indicate is after the job's first run, so I would expect the size to be almost the same as the full backup job.This is no big deal for me, I'm just trying to understand
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@Mathieu said in Backup size Full vs Delta:
@DustinB
My retention is set to 14, but as mentioned in the initial post, the size of the delta backup I indicate is after the job's first run, so I would expect the size to be almost the same as the full backup job.This is no big deal for me, I'm just trying to understand
Oh sorry, I completely misread that. That is odd then for sure that you're Delta backup initial is nearly double the used space.
Are these both the same VM getting backed up, maybe one is thin provisioned, while the other is thick provisioned?
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i done some tests. on same storage ofcourse.
Transfer:
delta 1st full - 5.98 GiB (1min)
full no compression - 5.05 GiB (4min)
full zstd compression - 1.84 GiB (3min)Indead looks weird. Time at least.
Im dunno if snapshot counts at that numbers, but it store on host storage anyway.As for about space on storage itself, it can depend on thin\think, storage compression\dedup, block size, data blocks backup.
