Successful System Recovery using Ignite-UX

archives can be recovered at another site). This means that even using make_net_recovery
shares most, if not all, of the same costs as those described in the
Tape cost topic.
A tape retention cycle that adheres to the appropriate retention periods for a potentially large
number of recovery archives on tape requires a great deal of disk space. In addition, it requires
fast, high-capacity tape drives to backup the data. These backups call for a retention cycle that
matches your recovery requirements, and you must have a method to easily determine the contents
of each tape, including the recovery archives stored on each.
Tape cost
The cost of tape-per-megabyte is much less than the cost of disk space. Furthermore, it allows for
off-site storage to provide a recovery solution in a loss-of-site disaster. There are cost factors
involved in tape use that are not limited to the cost of the tapes.
Consider the following potential costs:
• Each system must have its own tape drive because make_tape_recovery cannot access tape
drives connected to another system.
• It is not possible to boot from Fibre Channel tape drives so writing a recovery archive to one
means you must understand how to recover a system using dual-media recovery. (For more
information, refer to the ”Tape Recovery with No Tape Boot Support” section of the Ignite-UX
Administrators Guide.) This would remove the need to have a tape drive per system.
• It is not possible to boot a virtual partition (vPar) from a tape drive, which means you have a
choice to make in a vPars environment when using tape. Creating recovery archives for vPars on
tape requires the tapes to be recovered sequentially
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.
• There is the (much smaller) cost of cleaning tapes for tape drives that require them.
• There is the cost of someone changing tapes if tape drives are attached to individual systems.
• The cost of offsite storage for the tapes, as well as the retrieval of the tapes in an emergency,
must be considered.
• There is the cost of local storage for the tapes.
• There is the recovery speed: faster tape drives are quicker but they cost more (as does the
media). You need to balance the cost of the drive and media versus the speed of recovery
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.
Tape recovery has different costs than network recovery. Some of the costs are not strictly related
to tape recovery because if the tape drives are used for other things, the cost of cleaning tapes and
someone changing tapes may already be factored into the cost of operating the systems.
Assuming that each of 100 systems already had a DDS5 tape drive, that a recovery archive fits
onto one tape, that each tape cost US$4.31
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, and that there were at most six recovery archives
kept on tape, then the per system cost would be 100 x 6 x US$4.31 = US$2586.00 (excluding
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If you have most systems creating network recovery archives to one vPar and create a recovery tape for that vPar, you can then recover it
from tape, recover the latest recovery archives from the tape, and then recover the other vPars systems. The alternative is to use an Ignite-UX
server external to the vPars system.
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The speed described relates to more than just the speed of the tape drive. A slow, older system may not be able to perform stream reading
from the tape drive, which causes the recovery to be very slow even though the tape drive may be very fast. You should test recovery times to
ensure you identify the time needed to recover a system.
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This information was derived from the online purchase of DDS3 media (per tape) from the HP Small and Medium Business store on August
31, 2004, excluding the cost of shipping and any applicable sales tax.
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