FLARE operating environment

You can save data to them, but its not recommended, they contain amongst other things the FLARE operating system, the FLARE database LUN and the Vault (where write cache is dumped in the event of a major failure of an SP or the array). I've seen it said that if you must store data here, make sure there's no heavy i/o as it could affect the performance of the array as a whole.

thank you

Hi ,

The first five drives 0 through 4 in DAE0 in a CLARiiON CX4 are the system drives that contain the saved write cache in the event of a failure, the storage system‘s operating system files, the Persistent Storage Manager (PSM), and the FLARE configuration database. These drives are also referred to as the system drives. System drives can be used just as any other drives on the system. However, system drives have less usable capacity than data drives because they contain storage system files. In addition, avoid if possible placing any response-time-sensitive data on the vault drives. Also, the reserved LUN pool LUNs, clone private LUNs, write intent logs, clone, and mirror LUNs should not be placed on the vault drives

The first four drives of the vault contain the SP‘s operating system. After the storage system is booted, the operating system files are only occasionally accessed. Optimal performance of the storage system‘s OS requires prompt access. To ensure this performance, EMC recommends using high-performance Fibre Channel, SAS, and Flash drives for the vault.

The first three drives of the vault contain the PSM and FLARE configuration database. The PSM and FLARE configuration database are used for storing critical storage system state information. SP access to the PSM is light, but the system requires undelayed access to the drives to avoid a delayed response to Unisphere Manager commands.

All five of the vault drives are used for the cache vault. The cache vault is only in use when the cache is dumping, or after recovery when it is being reloaded and flushed to the drives. With the CX4 series persistent cache, this is an uncommon event. However, during these times, host I/O response to these drives will be slowed

In general, when planning LUN provisioning, distribute busy LUNs equally over the available RAID groups. If LUNs are provisioned on RAID groups composed of vault drives do not assume the full bandwidth of these RAID groups will be available. Plan bandwidth utilization for LUNs on vault drives as bandwidth of these RAID groups will be available. Plan bandwidth utilization for LUNs on vault drives as if they are sharing the drives with an already busy LUN. This will account for the CLARiiON‘s vault drive utilization. Bind the vault drives together as a RAID group (or groups). This is because when vault drives are bound with non-vault drives into RAID groups, all drives in the group are reduced in capacity to match the vault drive‘s capacity.

Vault drives may be used for moderate host I/O loads, such as general-purpose file serving. For these drives restrict usage to no more than shown in the table below.

Regards,

Suman Pinnamaneni,