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Changing RAID on PowerEdge 840
I just procured a Dell PowerEdge 840 on sale. It appears to have 4x70gb SAS drives in RAID configuration that shows only 1x70gb drive. How can I reset the RAID array so that I have access to all 4 drives?
theflash1932
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February 13th, 2012 12:00
Then you only have three options:
1. Leave it as is (recommended and standard). If the drives are configured in a RAID 1 (or mirror), then either drive can fail and your data will stay accessible, giving you the chance to replace the drive without so much as a reboot. In this configuration, the SAS 5/iR manages the RAID 1 (mirror), and presents the OS with a single "disk" to use. Because each drive is a mirror of the other, you would 1) only see the "mirror" in the OS, rather than the individual disks, and 2) only see the disk space of a single disk.
2. Create a RAID 0 (stripe). This is not recommended, because if a single disk fails, all data on both disks will be inaccessible/gone. There can be some performance improvements in this configuration, but should not be used unless a rigorous backup plan is in place. In this configuration, your OS will see a single disk of 146GB (somewhat less will actually be usable).
3. Use the controller in non-RAID mode. This treats each drive as an individual disk, performing no RAID functions. This is no different than having multiple disks connected to onboard ports on a motherboard - one disk dies, then the contents of that drive will be inaccessible/gone. In this configuration, your OS will actually see two separate 73GB disks.
theflash1932
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February 13th, 2012 09:00
What RAID controller does it have? Check during POST.
Mango1
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February 13th, 2012 11:00
It appears that the RAID is Dell SAS 5 v6.12.02.00. I can access it using . When I view it, it says it is SAS1068 and it looks like there is only 2 drives vs 4. I guess the other two are empty bays.
Mango1
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February 13th, 2012 17:00
many thanks. I'll see about getting additional drives. I see that I have 2 extra bays.
Mango1
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February 13th, 2012 17:00
one additional question, plz. I see that getting additional SAS drives is a bit expensive. Would it be possible to go SATA on this server? The general spec's leads me to believe it is possible....but wondered if it "is" possible, are there any "gotchas"?
theflash1932
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February 13th, 2012 19:00
SAS connectors will take SATA drives ... it is part of the spec (although the reverse is not true). You can mix SAS and SATA on the controller, but you cannot mix them within the same VD (not sure why you would want to though).