150 IBM ProtecTIER Implementation and Best Practices Guide
\_ 3:0:1:3 sdk 8:160 [active][ready]
\_ 2:0:0:3 sdq 65:0 [active][ready]
mpath8 (360050768028580f8c8000000000000e0) dm-3 IBM,2145
\_ round-robin 0 [prio=200][active]
\_ 4:0:0:2 sdbj 67:208 [active][ready]
\_ 1:0:0:2 sdd 8:48 [active][ready]
\_ 3:0:1:2 sdj 8:144 [active][ready]
\_ 2:0:0:2 sdp 8:240 [active][ready]
\_ round-robin 0 [prio=40][enabled]
\_ 1:0:1:2 sdah 66:16 [active][ready]
\_ 2:0:1:2 sdai 66:32 [active][ready]
\_ 3:0:2:2 sdaj 66:48 [active][ready]
\_ 4:0:1:2 sdbr 68:80 [active][ready]
10.5 User data and metadata pool: General recommendations
This section provides general recommendations for setting up metadata and user data pools
for optimum performance in your ProtecTIER environment. We also provide general
guidelines for expanding the ProtecTIER repository.
10.5.1 Metadata pool
Regarding the metadata pool:
Use balanced RAID 10 groups for metadata MDisks (use a layout according to your
planning requirements) with at least 4+4 members. The recommended number of
metadata RAID groups (MDisks) is determined by the Capacity Planning Tool during the
pre-sales process. This number can be 2 - 10, based on repository size, factoring ratio,
and performance needs.
Do not share the metadata pool with the user data pool.
Create a single pool for metadata that contains all the metadata MDisks.
Specify an extent size default of 256 MB for each metadata volume created.
For each metadata MDisk, create a single metadata (MD) volume to accommodate the full
size of each metadata MDisk, by using the
sequential virtualization type.
Balanced RAID 10 is defined as RAID group creation in Storwize V7000 and
Storwize V7000 Unified, which uses drives to form the array from different
enclosures. This setup protects against drive and enclosure failures, considering the
SAS chain and the disk spare protection.
A SAS chain is defined as a cabling scheme for a string of expansion enclosures
that provides redundant access to the drives inside the enclosures. This setup is
achieved by having both node canisters in the control enclosure in the
Quorum volume: The 1 GB MD quorum volume can be created on any metadata MDisk.