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Archive for the ‘Data Conversion’ Category

Festive fun with LTO

‘Twas the night before Christmas, when all thro’ the house
Not a creature was stirring, not even a mouse;
Save for the IT manager at a German TV channel attempting to restore some footage from their PresStore backup archive in time for a New Year ’s Day TV Show…

To this day we are not sure what was not working, but working it was not. The catalogue of the PresStore backups had been cleared, it was thought that the 200 x LTO4 tapes would no longer be needed, so now a frantic effort was being made to re-create the infrastructure and scan 200 tapes.

With a single LTO4 drive it was already going to be a matter of luck whether the right tape was found in time as even working 24 hours a day you could hope only to get through 40 or so tapes in the time available, and the re-cataloguing kept failing with configuration errors, and so came the call for help, followed by an IT manager in a Volvo bearing LTO tapes and an expression of angst.

One of the benefits of writing one’s own software for various backup formats is that you don’t need to worry about configuration, processing is pretty much a function of tapes drive numbers, and with 20 LTO5 drives running in less than 2 days the PresStore backups had been re-scanned, a catalogue created and the required data identified.

Restoration of the required data from the PresStore backup took about an hour and so with time to spare our hero was racing back under the channel to save the day.

I have no idea who the footage was of, someone I am too old to appreciate I am told, so I apologise now to any Bavarian parent whose New Year peace we were responsible for disrupting, but the happy smiling face of the IT manager made it all worthwhile.

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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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Mission creep with mail restoration

3,500 backup tapes containing Commvault Galaxy backups from which selected emails are required within 30 days might seem like a tall order, until the tapes arrive and turn out to be 1400 TSM backups on LTO2, 1200 Galaxy on LTO4, 900 NetBackup on LTO1 and LTO2, along with a selection of additional DATs and AIT tapes of unknown origin (it transpired that these were AS/400 SAVLIB). The water having been muddied it now turned to sludge as the court deadline to get the data turned out to be 30 days from 18 days earlier, so there were 12 days until the deadline. One other small detail, the email system in use had changed at some point from Notes to Exchange.

Planning around formats such as NetBackup and Galaxy where there is at least the option to position along tape to filemarks and get backup set information without having read every block of data is one thing, for TSM there was no option but to read every block of every tape and identify all of the file present.

Under such circumstances using the originating backup applications is not an option, for NetBackup and Galaxy where this would be possible, the infrastructure set-up requirement prior to starting work would take us past the deadline. With TSM it is just not an option. To meet the deadline tapes had to be “spinning” from day 0.

This is where the benefit of having written your own “non-native” restoration software and having spent years proving it in live situations reaps rewards. Rather than needing media servers to host drives & backup servers to host backup software, we were able to process the tapes using single PC systems each with 4 tape drives attached and scale up to 60+ drives running simultaneously on a 24/7 basis, filtering the file information as we went to identify Exchange backups and Notes files and where found process the tapes in question and restore the data. The deadline was met, not easily, but a day early.

Whilst there are cases where using the originating “native” backup application is the way to go, in a case like this being able to scale up processing with the relatively simple addition of Windows PCs each with multiple tape drives and no requirement for additional servers is what made it possible.

 

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NDMP Restoration – No filer required

The restoration of data that was backed up from NetApp and EMC appliances, when those appliances have been retired, has long been a source of angst for IT departments. Do you have to retain appliances in case data is needed? Do you just accept that data is lost or that legacy hardware will have to be re-commissioned if a restoration from an NDMP backup is required?

Altirium’s “restore-on-demand” service now provides a solution with NDMP support being an integral part of Altirum’s much vaunted ADR Suite tape restoration software. Whether you have NetWorker NDMP backups from a NetApp filer or NetBackup backups from an EMC Celerra, files can be restored from your tapes direct to USB disk and returned to you quickly.

Contact Mark Sear or Laura Sangster on 01296 658737 to find how your access to your NDMP backups can be retained without the main of maintaining legacy systems.

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eDiscovery and the monster in the vault

Past failure cannot be taken as a signpost for the way things will be in the future, so the inability of the US and UK financial regulatory authorities to spot the credit bubble from 20 paces, or the world’s largest Ponzi scheme even when pointed out to them in neon lighting, should not be taken as a sign that regulation can be ignored.

What is almost certain is that these regulatory paper tigers are about to be forced to become real, and with it will come new zeal for enforcing regulatory compliance leading to an increase in eDiscovery and eDisclosure requests.

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Data migration and the curse of multiplexed NetBackup

A bit unfair to single out NetBackup, any format that supports multiplexing can leave similar problems for anyone attempting an archive-wide data migration project. The problem is this, multiplexing involves the interspersing of data from several sources within a backup set. This gives improvements in backup performance but the payback is in potentially degraded restore performance, especially if attempting a complete restoration of data. Why?

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Data Migration – whatever happened to optical disk storage?

It is not so many years ago that the world of data storage was buzzing with the development of various optical data storage products from read/write magneto optical disks, ablative WORM and Phase Change optical disk. This was to be the future of high volume, long term archival storage.

So what happened? Back in the 1980’s hard drives were expensive, not much trusted and low capacity. Optical disk offered a far higher capacity, and being a removable media technology, the ability to expand storage by simply using more disks. Tape was then seen as a technology in transition, again not adequate on the capacity front, and there was a perception of reliability issues.

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Data migration – making a molehill out of a mountain

It is very easy to accrue data, and with large diverse systems it is very easy to accrue very large volumes of the stuff from a wide range of different places. The problem comes when you want to get the data from this massive archive and onto a new format of tape to be accessed via a new system.

The more complex the system the more pitfalls when attempting to migrate the data. Where data is being streamed from multiple sources a technique known as multiplexing is often preferred as this gives the best use of the bandwidth available for data backup. The problem comes with restoring as each data set is potentially spread across multiple tapes, and the restore process using the originating backup software might well require that each set be restored individually and so you can end up having to read each tape multiple times. This effectively means that if you have an archive of 1000 tapes, you have to read 5,000 or 10,000 tapes to restore everything.

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