System memory requirements

How to determine the system memory requirements for the IBM Storage Archive Enterprise Edition.

The system memory requirement for IBM Storage Archive Enterprise Edition depends on the number of tape drives that are attached to each node, and the number of files to be stored on a tape cartridge in the system. The following calculation produces an estimate of this system memory requirement in gigabytes (GB):

      2 × d × f + 1

where d is the number of tape drives connected to the node, and f is the number, in millions, of files/directories to be stored on each tape cartridge in the system. The value 1 accounts for the 1 GB (.93 GiB) of RAM that is required for the IBM Storage Archive Enterprise Edition program.

For example, if a system has six tape drives, with 3 million files that are stored on each tape cartridge (d = 6; f = 3), it is estimated that the node needs to have 37 GB (34.5 GiB) of free memory. In this example, it is suggested that you use a server with 64 GB of memory to allow the operating system and other software to use the remaining 27 GB:

        2 x 6 x 3 + 1 = 37

More memory is used when you run the eeadm tape reconcile command. The command does the reconciliation operation in two stages. The first stage processes the tapes one-by-one, without mounting the tape media. The command runs on the node where it is invoked. When the first stage is completed, the second stage distributes the reconciliation tasks across the IBM Storage Archive EE nodes, and mounts the tapes on tape drives. Multiple tapes are processed in parallel if enough tape drives are available for reconciliation. The first stage requires 2 x f GB of free memory for each tapes specified in command line parameter, on the node that is running the eeadm tape reconcile command. The second stage requires 1.5 x f GB of free memory for each tape drive that is used for reconciliation, on the node that is mounting the tape media.

In addition, your IBM® General Parallel File System (GPFS) system must be configured with adequate RAM. For more information, see Tuning Storage Scale configuration settings to optimize performance section.