Storage optimization

[perjonsson1960]

Folks,

We have repository extents that are around 280 TB in size.
Just now I realized that we have been using a block size of 1 MB, which is the recommended and default setting.
When I choose the 4 MB block size, it says that this is required for disks larger than 100 TB.
We have not seen any problems with the use of the 1 MB block size. Is it a problem?

Kind regards,
PJ

[david.domask]

Hi Per,

General rule of thumb is "use the defaults unless you know you have a reason to change the storage block size"

Our User Guide and Best Practices Guide have some additional details and explain why backups of 100 TB + disks are best done with 4 MB blocksize, but in brief unless you're seeing exceptional CPU / Memory usage on the repository during backup, probably it's fine to leave it as is.

For your larger workloads it might make sense to test backups / restores with larger block sizes and see if it meets your needs, but if you're not seeing issues, leave well enough alone and use 1 MB.

[perjonsson1960]

Thank you!

Now, when I read that 4 MB block size is recommended for backup files larger than 16 TB, I went to look at the job that backs up our file server (which has a full backup size of approx. 21 TB), and that job actually uses 4 MB blocks. So, I guess that back in the day, when I created that job, I somehow had information about that it would be good if I used 4 MB, although I had forgotten all about it now...
And in all the other jobs, the backup files are nowhere near 16 TB, so I guess it's all good.

Kind regards,
PJ