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Add Larger Drives to Perc 4 Raid 5 DELL 2850

So I have a server that has one huge raid 5 across 6 drives that is running out of space and failing drives. I know they should have made the OS separate but this is what we got.(could've used acronis)
We got new drives and replaced them one by one letting the drives rebuild over time.
The question is now that I have the drives in there and all is good, What is the best way to get the system to recognize the new hd space to go across all the drives? Keeping in mind it is one large raid 5 and a production server?
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Darktide0_0
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Darktide0_0
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1 Solution
 
IanThCommented:
you will need to backup the array and copy it of then rebuild the array if you add a bigger hdd to an array it acts like the old hdd not like a bigger hdd
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PowerEdgeTechIT ConsultantCommented:
Because the PERC cannot automatically or manually resize the array to fill the entire size of the disks (because it is larger than the current array configuration), you only have two options at this point:

- Do as Ian suggested and backup/image everything, create a new RAID 5 across your larger disks, then restore, or
- Create a separate RAID array using this addition space.  You can do this in the CTRL-M BIOS utility or through the OpenManage software.
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PowerEdgeTechIT ConsultantCommented:
This, of course, will require you to create a new partition/drive letter with it, as Windows will see it as a new "disk", so you will not be able to add its space to any existing partitions.
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Darktide0_0Author Commented:
While I am fine with creating a new partition or drive letter, it seems like there would be a performance issue with having two separate Raid 5's on the same array. Is that true or would it not even matter?

Normally I would just use acronis on the data partition, then rebuild the raid, then restore. This one is crazy though since everything is lumped together.
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PowerEdgeTechIT ConsultantCommented:
Obviously, since the two arrays are on the same physical disks, there could be a light to moderate performance hit, depending on how heavily used each array will be.  If performance is an issue, then backup/restore is the best way to go.  There can be complications when running multiple arrays across the same set of disks, particularly if the system firmware and drivers are not up to date.
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Darktide0_0Author Commented:
Dell tech gave me a tip:
Inside Bios turn off the initialization option. Then remove and rebuild the raid. HE said this would only remove the top level raid config (the part that has the size info) while keeping all the data. Gonna give it a whirl, worst case is I would end up doing the restore as we had talked about. Ever heard of this?
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PowerEdgeTechIT ConsultantCommented:
It will appear to work, but it is only a side-affect of a recovery method called a retag.  A retag simply tags each drive with the meta data for the array.  A retag is intended to be used to recover deleted or lost configurations and was never intended for use in this manner - again, the fact that it appears to work is only a side-affect.  From the Dell RAID engineers, this will cause instability in the array and create a situation where it is only a matter of time before the array fails completely, so if you will always have good reliable backups, then it will save some time in the here-and-now, but you will eventually need to reconfigure/restore it.  Also, this will fail immediately if done using different settings than the original array (stripe size, etc.).
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Darktide0_0Author Commented:
Right on, thank you very much for giving me the low down. I truly appreciate it. I will just do it the right way so I don't leave here with any guilt ; )
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Darktide0_0Author Commented:
Great inside information, saved my company future grief.
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PowerEdgeTechIT ConsultantCommented:
It is definitely quick and easy enough thing to do to be tempting, even in light of the warning, but the thing I usually tell people is you know someday - maybe today, maybe in a year - there will be a problem, and no matter when it happens, it will never be a good time, and today you know your backup is good - who knows what disaster is looming ahead.

Take care.
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