Change Storage Policy to RAID6 only but still RAID10

Hello demenoen,

This is normal since you still have volumes on your R10 DM.  If you are also running data progression then, you will need to let data progression finish before you will see the change in space. 

Please let us know if you have any other questions.

Hi Sam,

Thank you for the reply. Please note these are statistics for this particular volume which storage policy was changed weeks ago and data progression should be finished (snapshots are created everyday and expire after 2 days).

I assume it should left no data on R10 DM, is that correct?

Regards,

Damian

There will always be a small amount of data in Raid 10 DM. This is the configuration data that is stored on the disks for the system. It should be minimal. If Data-Reduction is used (Compression/Deduplication) it will use the Raid 10 DM space for the compression metadata.

Dell Storage Center OS 7.0 Data Reduction with Deduplication and Compression

https://downloads.dell.com/solutions/storage-solution-resources/Data-Reduction-SCOS-7.0-Dell-EMC-2018-(2100-SB-SC).pdf
Page 6: A minimum of six managed SSD (flash) drives plus a hot spare are required. SSDs provide the read performance required for metadata generated by data deduplication.

Since your screen shot shows active volume space I would confirm that you have all Volumes set correctly. I would also verify you have the correct stripe width set. Refer to page 234 of the Dell Storage Manager 2018 Administrator's Guide
https://topics-cdn.dell.com/pdf/dell-storage-manager_administrator-guide3_en-us.pdf

For the RAID 6 Stripe Width drop-down menu you should have the width set as 10 disks.

Hi Bob,

Thank your for the reply. We don't use deduplication and compression. According to these guides everything seems to be configured correctly.

Meanwhile we realised that there's no free space for RAID6 but RAID10-DM only in the Storage Type. Is it possible to somehow assign some allocated space for RAID10 to RAID6?

Regards,

Damian

The SAN will provision space as needed. To see your currently used and available space I would suggest to follow the steps on page 326 of the Dell Storage Manager 2018 Administrator’s Guide:
For each storage type, the data progression pressure report displays how space is allocated, consumed, and scheduled to move across different RAID types and storage tiers. Use the data progression pressure report to make decisions about the types of disks to add to a Storage Center.
1. Select a Storage Center from the Storage view. (Data Collector connected Storage Manager Client only)
2. Click the Storage tab.
3. In the Storage tab navigation pane, expand Storage Type, then select the individual storage type that you want to examine.
4. Click the Pressure Report subtab to view the data progression pressure report. By default, the most recent data gathered from the Storage Center is displayed.
5. (Optional) To view a previously generated data progression report, select a report from the drop-down menu. Reports are identified by the date and time at which they were generated.

You will see at the top below the Tier the Available and Allocated Space:
Disk Space Available - Total amount of disk space available on the disks of a Storage Center
Disk Space Allocated - Total amount of disk space allocated on the disks

Disk Allocated - Space reserved for volumes.
Disk Used - From the amount of space allocated, the amount that is in use by volumes.

Volume Allocated - Amount of space reserved for use by volumes after RAID is applied.
Volume Used - Amount of space used by volumes after RAID is applied.
I feel this can give you a better view of what is allocated, used, and available.

Dell Storage Manager 2018 Administrator's Guide
https://topics-cdn.dell.com/pdf/dell-storage-manager_administrator-guide3_en-us.pdf

Hi Bob,

Thanks for your explanation. However it was not the case. I contacted a support and it ended up with manually (copilot activity) moved data from RAID10 to RAID6. I got information that with SCOS 7.3.6 the space optimization feature will manage the space more automatically.

Regards,

Damian