The RAID configuration information is stored on the controller and on the drives. Any time the configurations do not match, the controller wants you to decide which one it should use. You always want to use the configuration on the drives in this case.
(The RAID battery keeps cache data alive on the RAID memory - it does not store configuration data for the array; configuration data is stored in non-volatile RAM on the controller itself - not the cache DIMM.)
Whether you put the drives into this system or another, the process will be the same - you will need to view the config first (View/Add - if there are multiple configurations (NVRAM / Disk), it will ask which you want to see). Once you like what you see, you then save the config on exit. Either way, it won't affect anything on the drives. All we are dealing with here is telling the controller which config to use.
It is possible that once you switch to RAID and accept the scary message, that the controller will recognize and accept the configuration automatically and everything will be fine. BUT if you see a message about a mismatch, you will need to save the Disk config in View/Add.
Moving the drives to another computer will make no difference - it will be exactly the same as doing it on this box - you will still need to accept the new/changing config. Don't afraid of the data loss message - changing between modes will not harm anything.
CTRL-M, Configure, View/Add is the utility used to read the headers from the drives. The only other way is to get a hex editor and a JBOD enclosure to inspect the individual disks, and unless you know what you are looking for, this will not mean anything to you (I.e. it will not say "disk 2 of 4 in RAID 5").
RAID Reconstructor is one such tool (will read and interpret RAID/drive metadata to piece things together) used to recover RAID arrays.
Thanks for the prompt replies. If we move the drives to another 2850 server (there's a second one available in the server room) that has already been set to RAID (vs. SCSI) in the BIOS, will it pick up the configuration from the drives? Will I need to wipe out the RAID configuration on the 2nd server first (obviously making an updated backup firrst).
I was also curious if there is some utility/tool that could be run from another boot drive (like XP lite) that may be able to read the drive headers to determine what the old configuration was.
Also, any recommended tool that may be able to backup each physical drive prior to any of the above steps so that recovery can be done back to the current (albeit broken) state. Standard backup software is really designed to backup logical drives so I was just curious if anyone knew of a tool that could see the physical drive. I'm also aware of some RAID recovery tools, but you really need to know the current RAID configuration for those to work (which we don't have).
You can safely ignore the scary "data loss" message ... up to a point. If the drives were set up in SCSI mode (no RAID), and set up in an OS-managed RAID (so there was only one drive letter), then switching to RAID mode in the BIOS would only lead to data loss IF you wrote anything to the drives (all of them).
If it was originally in RAID mode, then you must switch it to RAID mode. When you do, the controller will see the configuration on the drives ... you must go to CTRL-M, Configure, View/Add, and choose/save Disk View. This will import the configuration for use on the controller.
Great. Thanks again for the very prompt replies. Your comments fit 100% with what I would expect - just work with HP so wanted to confirm expected behavior on Dell. I'm still going to see if I can find a bit-level backup utility that can grab physical images of the disks (if possible) before I do anything. May be paranoid, but better safe than sorry. Thanks so much.
Thanks - will try this tomorrow. I had read a recommendation on another site that suggested removing the drives, switching the mode from SCSI to RAID, and viewing the expected configuration PRIOR to putting the physical drives back in. As the array information should be stored in the RAID controller's memory (and provided that memory/battery has not failed or been reset) then it should work without the risk of affecting anything on the existing physical drives, correct?
Also you can take out all disks, then you can swtich from SCSI to RAID with no fear. Then power off and re install all disks and power on. With this procedure no data will be lost.
There's already nothing to fear ... the data loss message can only cause data loss if you perform certain disk operations (like writing or initializing) in a different mode other than the one used to install the OS/data.
theflash1932
9 Legend
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16.3K Posts
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December 21st, 2011 16:00
The RAID configuration information is stored on the controller and on the drives. Any time the configurations do not match, the controller wants you to decide which one it should use. You always want to use the configuration on the drives in this case.
(The RAID battery keeps cache data alive on the RAID memory - it does not store configuration data for the array; configuration data is stored in non-volatile RAM on the controller itself - not the cache DIMM.)
Whether you put the drives into this system or another, the process will be the same - you will need to view the config first (View/Add - if there are multiple configurations (NVRAM / Disk), it will ask which you want to see). Once you like what you see, you then save the config on exit. Either way, it won't affect anything on the drives. All we are dealing with here is telling the controller which config to use.
It is possible that once you switch to RAID and accept the scary message, that the controller will recognize and accept the configuration automatically and everything will be fine. BUT if you see a message about a mismatch, you will need to save the Disk config in View/Add.
theflash1932
9 Legend
•
16.3K Posts
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December 21st, 2011 14:00
Moving the drives to another computer will make no difference - it will be exactly the same as doing it on this box - you will still need to accept the new/changing config. Don't afraid of the data loss message - changing between modes will not harm anything.
CTRL-M, Configure, View/Add is the utility used to read the headers from the drives. The only other way is to get a hex editor and a JBOD enclosure to inspect the individual disks, and unless you know what you are looking for, this will not mean anything to you (I.e. it will not say "disk 2 of 4 in RAID 5").
RAID Reconstructor is one such tool (will read and interpret RAID/drive metadata to piece things together) used to recover RAID arrays.
GenesisTech
1 Rookie
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7 Posts
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December 21st, 2011 14:00
Thanks for the prompt replies. If we move the drives to another 2850 server (there's a second one available in the server room) that has already been set to RAID (vs. SCSI) in the BIOS, will it pick up the configuration from the drives? Will I need to wipe out the RAID configuration on the 2nd server first (obviously making an updated backup firrst).
I was also curious if there is some utility/tool that could be run from another boot drive (like XP lite) that may be able to read the drive headers to determine what the old configuration was.
Also, any recommended tool that may be able to backup each physical drive prior to any of the above steps so that recovery can be done back to the current (albeit broken) state. Standard backup software is really designed to backup logical drives so I was just curious if anyone knew of a tool that could see the physical drive. I'm also aware of some RAID recovery tools, but you really need to know the current RAID configuration for those to work (which we don't have).
theflash1932
9 Legend
•
16.3K Posts
0
December 21st, 2011 14:00
You can safely ignore the scary "data loss" message ... up to a point. If the drives were set up in SCSI mode (no RAID), and set up in an OS-managed RAID (so there was only one drive letter), then switching to RAID mode in the BIOS would only lead to data loss IF you wrote anything to the drives (all of them).
If it was originally in RAID mode, then you must switch it to RAID mode. When you do, the controller will see the configuration on the drives ... you must go to CTRL-M, Configure, View/Add, and choose/save Disk View. This will import the configuration for use on the controller.
GenesisTech
1 Rookie
•
7 Posts
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December 21st, 2011 16:00
Great. Thanks again for the very prompt replies. Your comments fit 100% with what I would expect - just work with HP so wanted to confirm expected behavior on Dell. I'm still going to see if I can find a bit-level backup utility that can grab physical images of the disks (if possible) before I do anything. May be paranoid, but better safe than sorry. Thanks so much.
GenesisTech
1 Rookie
•
7 Posts
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December 21st, 2011 16:00
Thanks - will try this tomorrow. I had read a recommendation on another site that suggested removing the drives, switching the mode from SCSI to RAID, and viewing the expected configuration PRIOR to putting the physical drives back in. As the array information should be stored in the RAID controller's memory (and provided that memory/battery has not failed or been reset) then it should work without the risk of affecting anything on the existing physical drives, correct?
Capeto
1 Message
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September 5th, 2013 19:00
Also you can take out all disks, then you can swtich from SCSI to RAID with no fear. Then power off and re install all disks and power on. With this procedure no data will be lost.
Let us know!
theflash1932
9 Legend
•
16.3K Posts
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September 5th, 2013 19:00
There's already nothing to fear ... the data loss message can only cause data loss if you perform certain disk operations (like writing or initializing) in a different mode other than the one used to install the OS/data.