Data Recovery Weekly

A customer walks in and says: We need to recover a FATX volume, can you do that? - Sorry, no. Various exotic filesystems, btrfs, logfs, and even ReiserFs have always been considered a job for a data recovery serivce, not an automated software. Software is cheap, but only resolves common cases by applying typical solutions. Data recovery service is expensive, and applies its high fees toward the difficult cases, e.g. writing custom software to deal with just one specific case. Lately, there is an influx of requests for something nonstandard. The latest hit was - We have ReiserFs on the RAID5. - Okay, no problem. Turns out there was a problem. The RAID5 was using 512 bytes per block. JMB 393 controller. Oops. So far we have delayed parity (from HP SmartArray), Promise RAID 6 with its non-standard Reed-Solomon, Promise 1E interleaved layout, exFAT filesystem recovery . The capability to recover RAID with a block size of 512 bytes is in the pipeline, currently undergoing testi...

Recently we set to develop the algorithm to automatically recover RAID 5 array with delayed parity , as implemented by HP SmartArrays. Today we have mostly finalized the work. From this day on (build 306 onwards) ReclaiMe Free RAID Recovery is capable of recovering such arrays.

I recall we discussed that earlier, that our ReclaiMe Free RAID recovery software (and pretty much any generic RAID recovery software, like Runtime's RAID Reconstructor) does not actually work with RAIDs. It works with models of RAIDs instead. Data recovery service view on RAID5 more like "disks (by specific vendor), controller (also by specific vendor), and cables". The software sees it like 1 2 P 3 P 4 P 5 6 and pretty much nothing else. The problem arises when the actual data does not match the model used in software. The synchronous array (below) cannot be described in terms of the asynchronous model (above). 1 2 P 4 P 3 P 5 6 So the software has to acount for all possible models of the RAID 5, of which there are quite a number. We're currently working on automatic analysis of the so-called delayed parity arrays, used in HP SmartArray controllers. This subtype of RAID5 does effectively have two distinct stripe sizes, one for data and the other (...