4 Posts
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3414
December 24th, 2019 11:00
SC5020, Red Hat: How to SCSI Unmap to reclaim space?
Storage: SC5020
OS: Redhat 6.9 Clustered.
I did 750GB db restoration, during the job, I had to write and delete backup files on 1.5TB volume. Now the volume is pretty much empty (99%). However, SC5020 shows the volume is 97% full.
It seems as the space emptied out in Red Hat doesn't reflect to SC5020. What is the proper way and command to send space reclamation from Red Hat 6.9 to SC5020?
Thank you in advance.
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Sungpill Han
4 Posts
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December 26th, 2019 09:00
To share with anyone.
1. from RHEL, # fstrim -v /dir1 (this will send SCSI UNMAP command to SC5020)
2. Expire all snapshots and coalesce last snapshot to Active Space. This will remove all space occupied by snapshots and truncate the whitespace.
dwilliam62
4 Operator
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1.5K Posts
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January 9th, 2020 10:00
Hello,
Just a quick note. It's up to the filesystem to manage this. Not all filesystems support UNMAP.
What filesystem are you using for your cluster?
Common filesytems like EXT4 or XFS should have the option 'discard' in the /etc/fstab file. Enabling UNMAP on each mounted volume you want UNMAP enabled on. Or for local SSD drives as well.
Regards,
Don