Posts Tagged ‘Tape migration’
TK50 data recovery, look out for media degradation
August 24th, 2009 | Author: Mark
TK50 was a major player in tape backup on VAX/VMS systems several years ago. Being fundamentally ½” (half inch) tape of the type used in open reel drives, but housed as DLT style cartridge, it suffers from the same long term storage problems as some brands of 1/2″ media. TK50 drives could store 70MB of data, and took quite a long time to fill, so have long since ceased to be a viable backup option even if you can find drives and media. But, there are a surprising number of tapes out there with data on them and recent weeks seem to have brought forth a flurry of requests to get data from them, and in one case to copy some. In a high proportion of these cases the data transfer operation has ended up being a data recovery exercise involving considerable work in the lab.
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eDiscovery and the monster in the vault
August 4th, 2009 | Author: Mark
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.
Data migration and the curse of multiplexed NetBackup
July 15th, 2009 | Author: Mark
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?
Data migration – making a molehill out of a mountain
June 30th, 2009 | Author: Mark
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.
