I have a server with 8x SAS drives attached to hardware LSI RAID controller (MegaCli64) and all 8 drives are configured as single RAID 10 array.

I now want to remove 2 drives and replace them with bigger drives. Result should be one RAID 10 array of 6 drives and second RAID 1 array of 2 drives.

OS : CentOS 6

How can I reduce LSI raid array and remove 2 drives without data loss so that 2 drives could be removed? Server downtime is no problem.

From Google I see that MegaCli64 -LDRecon could help but I have never used it and don't have a test server at present to experiment.


[root@n ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on  
/dev/sda2              49G  8.9G   37G  20% /  
/dev/sda5             2.1T  1.6T  457G  78% /backup  
/dev/sda1             388M   93M  275M  26% /boot

All drives are of type ext4 in Linux.

/backup is not important, I can easily copy data and copy it back but I certainly do not want to reinstall OS and all configurations and setups of various softwares. It would demand too much time.


All current disks (8 in number) are of 600GB in size type SCSI 15k RPM. I want to replace 2 drives with new 4TB drives type SATA 7K RPM.
This is an Supermicro F627R3-R72B+ server with LSI 2208 controller.

  • Can you provide the drive sizes and types you're talking about? – ewwhite Oct 24 '14 at 19:13
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    I would never perform a major change to a RAID system without having a backup first. If you do have a backup, I'd suggest just rebuilding the RAID arrays how you want them, then copy the data back from your backup. Just because something is possible doesn't make it a good idea. – yoonix Oct 24 '14 at 19:54
  • Updated question to reflect drive size and types. – Jai Oct 24 '14 at 20:56
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    All current disks (8 in number) are of 600GB in size type SCSI 15k RPM. I want to replace 2 drives with new 4TB drives type SATA 7K RPM. – Jai Oct 24 '14 at 21:19
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    @ewwhite this is an Supermicro F627R3-R72B+ with LSI 2208 controller. – Jai Oct 25 '14 at 6:32

You can't do this. You can only remove one disk at a time using the -LDRecon Rmv switch, and given the scale of drives you're speaking about, this would probably be the most complex path you could possibly take to get where you want.

  • Do you have an option to add external storage?
  • I'd suggest a system backup and restore or rebuild to get to the desired capacity.

On the HP ProLiant Smart Array side of things, shrinking of LogicalDrives is a very new feature, and even then, it's not a recommended approach.

Shrink an array (restripe the data on an array to occupy fewer physical drives, then remove the excess drives from the array)

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  • Accepted answer as "system backup and restore". What would be better, using DD command or using clonezilla in this case? – Jai Oct 25 '14 at 17:21

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