HP StorageWorks Scalable File Share System Installation and Upgrade Guide Version 2.2

SFS20 storage — overview and planning 5–25
5.3.5 Configuring SFS20 arrays attached to Object Storage Servers
When configuring SFS20 arrays attached to Object Storage Servers, you must take account of the following
factors:
• There can be a maximum of four SFS20 arrays for each Object Storage Server (that is, eight SFS20
arrays for an Object Storage Server pair). This maximum configuration fully utilizes all available
Smart Array 6404 adapters.
• The maximum supported size of a LUN on an SFS20 array is 2TB.
• The maximum number of disks that an SFS20 array can contain is twelve.
• You can configure the SFS20 arrays with either ADG or RAID5 redundancy, except where 500GB
disks are used, in which case only ADG redundancy is supported. (See Section 5.3.3 for more
information on RAID5 and ADG redundancy).
• Three disk sizes can be used on SFS20 arrays attached to Object Storage Servers: 160GB, 250GB,
and 500GB. Where 160GB and 250GB disks are used, one OST LUN is typically configured on
each SFS20 array. Where 500GB disks are used, two OST LUNs are typically created on each array.
Although it is possible to configure additional OST LUNs on an array, such a configuration has a
severe impact on performance, and is not recommended for normal configurations. Refer to
Appendix B of the HP StorageWorks Scalable File Share System User Guide for more information on
how such a configuration affects performance.
• The best performance is obtained from a single disk group populated with as many disks as possible.
The default disk group size is eleven disks.
The size of disks used, the maximum LUN size of 2TB, and the type of redundancy used, determine
the maximum number of disks that will be in a disk group, as follows:
• If 160GB disks are used, the maximum number of disks that can be in a disk group is eleven
(plus one spare disk for use in case of disk failure).
• If 250GB disks are used with ADG redundancy (the default), a disk group can contain a
maximum of eleven disks (plus one spare disk for use in case of disk failure). However, if RAID5
redundancy is used, the maximum number of disks that can be in a disk group is ten, plus up to
two spare disks for use in case of disk failure.
• If 500GB disks are used, only ADG redundancy is supported, and a single disk group of eleven
disks, plus one spare disk, must be configured.
2 140GB
1
admspare south[1-2] The spare administration LUN.
11GB svcspare south[1-2] A spare service LUN for the south1
and the south2 server pair.
133% of the
remaining
capacity in the
disk group.
mds south[1-2] The second of the pair of LUNs for
the MDS service in one of the file
systems.
1 All of the
remaining
capacity in the
disk group to a
maximum of 2TB.
mds south[1-2] The second of the pair of LUNs for
the MDS service in the second file
systems.
1. Can be configured to a different size.
Table 5-6 SFS20 arrays attached to the administration and MDS servers — two file systems
Array Disk Group Size Role Connected to Notes