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November 16th, 2012 07:00
PE r810 RAID expansion
Hello all,
This is the first time posting to the Forums on delltechcenter.com, so my apologies in advance if this question is not posted to the correct group.
My question.
I have a PE r810 server with a PERC H700 integrated storage controller. There are 4 x 130GB SAS HD's installed in this server. These drives are configured in a RAID 5 configuration. My question is: Can I add 2 more 130GB SAS HD's and expand the current RAID 5 config, to include the 2 additional disks, without disrupting the existing RAID 5 "virtual disk"? Or will expanding the RAID 5 config mean that the existing RAID 5 "virtual disk" will be destroyed? In which case, I will need to run a backup of the contents of the "virtual disk" before I expand the RAID 5 config and then perform a restore after the RAID 5 config. has been expanded.
Thanks,
Eric.
DELL-Sam L
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November 16th, 2012 09:00
Hello Eric,
You can add the drive to your virtual disk raid 5 without any issues. What you will have to do is do a reconfigure in the bios of the perc card & it will add the new disk to your raid5. Now it will impact performance by about 30% so if that is too much then it is best to do off production hrs. Also as always it is best to have a backup just incase there is any issues with the expansion of the raid5.
Let us know if you have any other questions.
ewhb
22 Posts
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November 16th, 2012 11:00
Sam,
Can this also be accomplished using the "Storage" functions available in Openmanage Server Administrator? This is installed on this server and would be very handy if this can be done through this interface.
Thanks,
Eric. :)
ewhb
22 Posts
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November 16th, 2012 11:00
Sam,
Also, the additional disks haven't been added to the server yet. Can the additional disks be added to the server with it up and running or should they be added to the server with the server powered down?
Thanks,
Eric.
DELL-Sam L
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November 16th, 2012 12:00
Hello Eric,
Yes you can use OMSA to configure the VD when you add the new drives as that is fine. Also you can add the drives as your R810 supports hot plug drives.
Let us know if have any other questions.
ewhb
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November 20th, 2012 13:00
Hi Sam,
I successfully expanded the RAID array. There is now approx. 240GB more of usable disk space. The issue I am having though is having the O/S on the server recognize that additional disk space. The server is running Oracle Enterprise Linux 5.8 (basically Redhat Enterprise 5.8) and it is not recognizing the additional disk space now available. Linux sees the RAID 5 virtual disk as one disk, /dev/sda, with multiple partitions/logical volume groups. I want to either extend an existing volume group or create a new one. But I can't, as the O/S doesn't see the additional disk space. I have read that there is RAID BIOS setting for "Virtual Sizing" which enables "Online Volume Extension". Is this what is required for the O/S to see the additional disk space, or is there something else that needs to be done?
Thanks,
Eric.
DELL-Sam L
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7.6K Posts
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November 21st, 2012 11:00
Hello Eric,
If you haven’t already scan for the SCSI bus to see if the new LUN shows then I would try that. The command to scan the bus if you need it is:
echo “- - -“ > /sys/class/scsi_host/hostH/scan
You’ll need to choose the right value of H for example 0, 1, 2, etc … depending on which HBA it is. If that still fails to make the new space present then you may have to reboot the server. After that you should be able to see the new space on the block device (in fdisk or parted) and then you can repartition or expand as necessary.
Let us know if you have any other questions.