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On a Dell R310 server with Perc H700 RAID controller.

I have 1 virtual disk configured as Raid 1 but with only 1 physical SAS disk attached and the other missing. This virtual disk has been configured with fresh CentOS 6.9 and boots normally.

I now have another physical SAS disk containing some recovered data. Can I create a second virtual disk again containing only 1 disk WITHOUT loosing the data on it and then simply mount it in the OS? I am afraid it will initalize and erase the disk if I do that. How can this be accomplished? We don't have other options for reading the SAS drive. I am not able to find any guides relating to this scenario.

Reading the manual it seems I should be able to create a VD and then NOT initialize it. Would this make it accessible to the OS (f.ex. like would it allow linux to create a /dev/sdX device)?

lightspeed
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2 Answers2

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Full man page for MegaCLI is given below:

https://web.archive.org/web/20170626231838/https://www.dokterlinux.id/hardware-raid-setup-using-megacli-on-linux/

The command to pop a physical drive into the chassis and flip it into online state is:

# MegaCli -PDOnline -PhysDrv [E:S] -aN
John Greene
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another physical SAS disk containing some recovered data

Was this disk "behind" a PERC RAID controller in its original configuration when the data was written to it? If so, and if it was configured as a RAID0 (or in a 2-disk RAID1), then the VD creation without initialization option should work.

If the disk was originally connected to a SAS HBA (non-RAID), then this likely won't work quite as well for recovering the data since the H700 does not support pass-through mode.

When you create a new virtual disk on the added drive, some data (metadata) will be written to the beginning of the drive. If the disk was originally non-RAID, then this will be overwriting some or all of the disk's partition table, and potentially even some beginning sectors of the actual partition / data.

We don't have other options for reading the SAS drive

You could always purchase an LSI 9207-8i or similar internal 6Gbps SAS HBA if you want to really be safe - they're quite inexpensive too, now that 12Gbps SAS is mainstream.

JimNim
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