Deleted, Missing or Malfunctioning LUNs on a HP P4000/P4500 Storage Server

  • Added:
    Sep 09, 2014
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Deleted, Missing or Malfunctioning LUNs on a HP P4000/P4500 Storage Server Photo by Tony Ohare

Here at Manchester Data recovery we try not to be too technical when it comes to explaining how we do things. But this is something that we can only really do if the technology allows for it to be so. Sometimes however such devices as the HP P4000 and its P4500 counterpart make for slightly more complex explanations because of the nature of the technology involved and the reasons why it can fail.

When it comes to these SANs (Storage Area Networks) which are normally more than one ‘node’ strung together to form what is known as a ‘cluster’; there are a number of issues that can arise which can make life difficult if you are a heavy business user. The whole notion of using a SAN (Storage Area Network) and multiple ‘nodes’ is to allow for the transfer of large volumes of data across a network using IP and Ethernet protocols.

Within these setups is what are known as LUNs (logical unit numbers) which to give them a slightly less complicated definition would be an address on a hard drive. If you can imagine certain areas of the recover external hard drive contained within a ‘node’ being allocated a LUN (rather like a street name!) then LUNs are slightly less phasing. A LUN (logical unit number) is the area to which certain data is stored because it has been degreed that it should be the case when the ‘node’ was originally set up.

When it comes to dealing with the problem of missing or deleted LUNs you may find that HP (who purchased the Left-Hand server brand and all that went with it) will tell you that the data is unrecoverable. Indeed it has been the case since the inception of the HP P4000 and P4500 range from 2008 onwards that HP have said data attached to missing LUNs is lost forever and it unrecoverable.

We at Manchester Data Recovery say this is not the case and we have developed (in conjunction with our engineers) a range of bespoke forensic and reverse engineering recovery methods that allow for the recovery and reconstitution of SD card data recovery that would have otherwise been considered lost alongside a deleted or missing LUN.

The problem of missing LUNs may occur if you try to mount an iSCSI volume that is unfamiliar to the existing ‘node’ (i.e. has not previously been a logical unit number associated with the device). It may also occur if you have demounted and logged out of the LUN with perhaps a view to adding it to a Linux server. There are a variety of different reasons as to why this may occur.

If you have found that you are unable to access data from a drive or series of drives within a ‘node’ and the reasons displayed refer to missing or deleted LUNs then Manchester Data Recovery Services UK can help. Our engineers are experienced in dealing with the problems associated with missing, deleted or corrupted LUNs and have helped a number of clients retrieve data from devices that had otherwise been considered unrecoverable. They are also experienced in dealing with problems arising from missing LUNs as displayed through the HP Store Virtual Centralized Control Management Console.

For more information contact our engineers at Manchester Data Recovery on 0161 8710788 Monday to Friday 9am to 6pm and they will take you through an initial assessment of the problem and offer you a variety of services dependent on your budget and timescale for recovery.  Contact our engineers before writing off your SAN ‘node’ as unrecoverable thus losing valuable information, precious time and money.

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