storage pool for tiering & data aggregate

[ckirim]

Hello all,

I have 9 SSD's on my storage system. I want to ask, whether I use those SSD for tiering (as storage pool) and simultaneosly for standard data aggreate. 9 X 400 SSD provide me net 2TB usable space in Raid dp .And I want in this same raid group split %50 for tiering %50 for data read&write operations. Is that possible?

thanks

[aborzenkov]

No, NetApp does not support automatic tiering. FlashPool is cache - SSD disks do not increase available space. Sort of manual tiering is possible using volume/LUN move, but no better granularity.

[Naveenpusuluru · Accepted solution]

NetApp will not support storage tiering. You can use thos falsh drives to configure flash pool.

Creating a Flash Pool

You create a Flash Pool by enabling the feature on an existing 64-bit aggregate composed of HDD RAID groups, and then adding one or more SSD RAID groups to that aggregate. This results in two tiers for that aggregate: an SSD tier and an HDD tier.

Before you begin

• You must have identified a valid 64-bit aggregate composed of HDDs to convert to a Flash Pool.
• You must have determined write-caching eligibility of the volumes associated with the aggregate, and completed any required steps to resolve eligibility issues.
• You must have determined the SSDs you will be adding, and these SSDs must be owned by the node on which you are creating the Flash Pool.
• You must have determined the checksum types of both the SSDs you are adding and the HDDs already in the aggregate.
• You must have determined the number of SSDs you are adding and the optimal RAID group size for the SSD RAID groups.

  Fewer RAID groups in the SSD cache reduces the number of parity disks required.

• You must have determined the RAID level you want to use for the SSD tier.
• You must have familiarized yourself with the configuration requirements for Flash Pools.

About this task

After you add an SSD cache to an aggregate to create a Flash Pool, you cannot remove the SSD cache to convert the aggregate back to its original configuration.

You can change the RAID group size of the SSD cache, but you cannot make this change until after SSDs have been added. Once drives have been added to a RAID group, they cannot be removed. If you know that you want to use a different RAID group size than the default SSD RAID group size, you can add three SSDs at first. Then, after you update the RAID group size, you can add the rest of the SSDs.

By default, the RAID level of the SSD cache is the same as the RAID level of the HDD RAID groups. You can override this default selection by specifying the raidtype option when you add the first SSD RAID groups. Although the SSD cache is providing caching for the HDD tier, the SSD RAID groups are integral to the health of the aggregate as a whole. An SSD RAID group that experiences a failure that exceeds the RAID protection capability of the RAID level in use takes the aggregate offline. For this reason, it is a best practice to keep the RAID level of the SSD cache the same as that of the HDD RAID groups.

There are platform- and workload-specific best practices for Flash Pool SSD cache size and configuration. For information about these best practices, see Technical Report 4070: NetApp Flash Pool Design and Implementation Guide.

Steps

1. Mark the aggregate as hybrid-enabled:
   >storage aggregate modify -aggregate aggr_name -hybrid_enabled true

   If this step does not succeed, determine write-caching eligibility for the target aggregate.

2. Add the SSDs to the aggregate by using the storage aggregate add-disks command.

   You can specify the SSDs by ID or by using the diskcount and disktype parameters. You do not need to specify a new RAID group; Data ONTAP automatically puts the SSDs into their own RAID group.

   If you plan to change the RAID group size for the SSD tier, you should add only three SSDs in this step.

   If the HDDs and the SSDs do not have the same checksum type, or if the aggregate is a mixed-checksum aggregate, then you must use the checksumstyle parameter to specify the checksum type of the disks you are adding to the aggregate.

   You can specify a different RAID type for the SSD tier by using the raidtype option.

3. If you want a different RAID group size for the SSD tier than for the HDD tier, change the SSD RAID group size:
   >storage aggregate modify -aggregate aggr_name -cache-raid-group-size size
4. If you did not add all of the required SSDs in the previous step, add the rest of the SSDs by using the storage aggregate add-disks command again.