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Storage not claimed after freeing devices.
Team,
We have R3 devices(snapvx from srdf luns) for DR test. We have deleted the snapshots and then did free devices. We wanted to use those devices and storage group again, so we did not delete. After freeing devices, the allocated tracks came to 0% but still storage is not being reclaimed. Am i missing something here ? Do we have to definitely delete the luns to reclaim space ?
DELL-Josh Cr
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September 23rd, 2022 07:00
Hi,
Thanks for your question about reclaiming free space. This article may help. https://dell.to/3DKSR0X
Let us know if you have any additional questions.
Vara5a3
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October 4th, 2022 09:00
I am not able to view the above provided link.
DELL-Josh Cr
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October 4th, 2022 09:00
Are you logged in when you go to the article? Here is the contents of it.
Instructions
There are three types of Allocated tracks
1. Unwritten Allocated Tracks --> Thin Pool space that is preallocated / allocated to a TDEV, but contains no host written data (Basically unused storage within a thin pool, this can be done using the command below.)
symdev -sid1234 allocate -devs XXX:XX
a. Unwritten Allocated Tracks with Persistent flag
b. Non-Persistent Unwritten Allocated Tracks.
2. Zero Based Allocated Tracks --> All the extents / Tracks on the TDEV contain zeros (Tracks can contain zeros due to filesystem or database formatting methods depending on the underlying platform)
a. Persistent
b. Non-Persistent.
3. Written Allocated Tracks --> Tracks containing host written data. (e.g. Files, Databases etc)
1a. can be restored to the thin pool using reclaim -persistent command
1b. can either be restored using free or reclaim command
2a. can be restored to the thin pool using reclaim -persistent command
2b. can be restored to the thin pool using reclaim command
3. Written tracks can only be restored using free -all command.(The device must be not mapped or Not Ready)
Note: Free -all command can be used with all three scenarios , basically it will clear the allocated tracks whether it has written data or unwritten or zero written tracks, Please use this command carefully.
Note: only deleting the files on a partition /FS will remove the pointers to the data, but data is available and not marked as 0 based thus reclaim or free without -all option will not restore that, in Linux Systems we can run a fstrim command to reclaim space after deleting the Files on the partition (fstrim command will discard any unused tracks/blocks )
Note: space reclamation process is non-disruptive and can be executed while the targeted thin device is fully available to operating systems and applications.