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Archive for November, 2015

Tape Restoration Services

Attempting to process large numbers of tapes natively (i.e. using the the originating backup application and IT environment) can prove to be a daunting task when large volumes of data are needed quickly. Most infrastructures are designed around getting data written out to tapes, but only sometimes needing to restore. This is not an adverse criticism, if daily restores are needed then either it is time to stop getting IT equipment from fire sales or there are some staff training issues to address.

However, when a large volume of data is needed quickly from a broad cross-section of backup tapes, perhaps a legal case requiring email data spanning several years, how can it be done?

In the case of one UK insurance company they had over 1000 LTO tapes, LTO1 to LTO3, containing Backup Exec backups from a number of Windows based systems, these included MSSQL backups, Exchange IS backups, and user data file backups from a number of servers running SIS (single-instance-store). They were not in a desperate hurry, but they knew a requirement to disclose data was likely in the next 4 months and that it could include email and user’s file data, so they were looking for a 3rd party tape restoration service.

As fortune would have it we had just released our latest version of our ADR Tape Restoration software suite, complete with a new module to handle SIS backups without the need to have SIS installed, and the Exchange and file data were duly restored to USB disks. Our processing for this, to meet the deadline, meant using multiple drives restoring in parallel on standalone PC systems, no need to Exchange servers or Windows servers with client systems. Each time a set of 4TB USB3 drives became full they were shipped post-haste to the customer so they could introduce the data to their new archive management system, and by the time they needed it they had it all in place.

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Unlucky 13?

Being a generally optimistic person and not believing in bad luck, not even if someone turns up with an OnStream cartridge, the prospect of 13 x LTO2 tapes containing ARCserve backups was not of particular concern. Then the additional information was provided, they had been to another company for restoration and there was a problem with the data, the backups were corrupted and could not be restored, “was there anything we could do”?

Not having seen the tapes it was not honest to give more than a cautiously optimistic opinion. No-one here had encountered a corrupted ARCserve backup since some problems with Adaptec 1542 cards and MSDOS with too much memory installed back in the early 1990s. It seemed more likely we would find that they were either not ARCserve at all, or else were encrypted.

When the tapes arrived it all became clear. They were ARCserve with multiplexing, which means that the backup data from several backups can be interleaved and any attempt to proceed in a linear manner without first loading and interpreting the ARCserve MUX (multiplex) tables is going to end in tears, or at least with worthless data. The next challenge was restoration within an average life-span, restoring a single backup would be relatively straightforward one the MUX tables had been correctly interpreted, but with over a hundred backups per tape the idea of restoring one set at a time was not overly appealing as each tape would have to be read over 100 times, effectively turning a 13 tape restore into a 1300+ tape restoration exercise. This is where the benefits of developing software for tape restoration come to the fore, and being able to modify code to enable the simultaneous processing of all backups so each tape took less than 3 hours to read.

Once the tapes had been catalogued the required Exchange email data was located. Anyone fancy a guess at which number tape it was on? Sorry, that would have been too poetic, it was on tape 7.

 

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