Backup capacity limitation.

[panot4u]

Hi All,

Do we have any size restriction of taking the backup daily/weekly/monthly?

 

[dcsapak]

hi,

what do you mean exactly? there is no inherent size or frequency limit for backups.

 

[panot4u]

Normally when we buy a backup appliance such as commvault/Veritas, then mentioned backup capacity limitation such as 20TB per day based on the hardware etc, Do we have any such limit or specific hardware configuration for PBS.

Consider I need to take 20TB of backup per day?

 

[dcsapak]

well if your hardware is capable of that, it should work... pbs will not impose any artificial limits on it. note that all backups on a datastore are deduplicated, so in comparison with other
backup solutions, it will probably use less space

 

[panot4u]

well if your hardware is capable of that, it should work... pbs will not impose any artificial limits on it. note that all backups on a datastore are deduplicated, so in comparison with other
backup solutions, it will probably use less space

What will be the minimum hardware required to take 20TB backup?

 

[ness1602]

20TB of disks
just kidding, usually if you are working with zfs i would say 16gb ram, 4 core machine. If you need speed,you could add special device to your raid pool.

 

[Dunuin]

And PBS will safe those 20TB as files of max 4 MB in size (called chunks). So thats probably around 5-20 million files that need to be read/hashed when doing maintaince tasks. And because of deduplication these reads tend to be a bit random and aren't purely sequential. So you basically want good IOPS performance, especially for the metadata.
So you probably want 25TB + X TB (parity) of SSDs for ZFS if you care about performance.
Or atleast SSDs as ZFS special devices for storing metadata if a pure SSD pool isn't an option.

When using HDDs only or network shares, dont wonder when maintaince tasks like a verify run for days/weeks. Here a full verify on a 4x HDD raidz1 over NFS took 4 hours for just a 2/3 TB. So 300 hours if you extrapolate that to a 25TB datastore filled up to 20 TB (With ZFS you want 20% of your pool always free, because of copy-on-write).

 

[ness1602]

I had 4x4tb Ironwolf and monthly verification would last for a few hours. So yes, verification will be maybe in tens of hours for 20tb and HDDs.