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20 Dell PS Series Storage: Choosing a Member RAID Policy | TR1020 | v 4.7
6 Converting or migrating from a member RAID policy
There are different methods available to convert or migrate from one RAID policy to another with PS Series
arrays. These options can include:
 Online conversion
 Array evacuation
 Online volume migration
 Backup and restore
6.1 Large disk policy for RAID 50 and RAID 10
Beginning with version 7.0.0 firmware the Group Manager GUI and the CLI allow users to configure RAID 50
for members using disks with a capacity of less than 3 TB only. The CLI allows users to configure RAID 50 for
members using disks with a capacity of 3 TB or greater, although this configuration is not recommended due
to decreased RAID protection and reliability for large disk sizes.
For the PS models that support greater than 6 TB disks, RAID 10 is not recommended. RAID 6 should be
used instead.
In addition, Dell recommends against using RAID configurations that do not use spare disks. You should
convert all group members that are using a no-spares RAID policy to a policy that uses spare disks.
Group Manager GUI RAID Policy rules
RAID Policy
Configurable in GUI
Best Practice for Business-Critical
RAID 6
Yes
Yes
RAID 10
Yes
No for HDD or SSD capacity greater than 6 TB.
RAID 50
Yes for disk capacity smaller than 3 TB
No for HDD disk capacity of 1 TB and larger.
RAID 5
No
No
6.2 Online conversion
With an online conversion, the migration occurs while the member remains online (in the group) if the new
RAID policy provides the same or more space as the current policy. Conversions can take a long time and
should be scheduled during off-peak times or when the workload is light.
The following online conversions are available in the Group Manager GUI and the CLI:
 RAID 10 to RAID 50, or RAID 6
 RAID 50 to RAID 6
Note: RAID 5 and RAID 6 have no online conversion options. The only way to convert RAID 5 or RAID 6 to
a different RAID type is to reset the array and initialize with a different RAID policy.