[CentOS] OT: Suggestions for RAID HW for 2 SATA drivesin DellPowerEdge SC

Feizhou feizhou at graffiti.net
Fri Aug 31 15:59:26 UTC 2007


>> Another route you can go is getting a PCI/PCIe/PCI-X BBU 
>> RAM/NVRAM card 
>> to put an external journal on to speed up fsync performance for 
>> filesystems like ext3 over software raid since these cards 
>> can go beyond 
>> 1GB of memory unlike hardware raid cards that usually max out 
>> at 256MB.
> 
> What are some of these BBU NVRAM cards that I keep hearing people
> talk about? I would love to check them out.

http://www.umem.com/Umem_NVRAM_Cards.html
http://www.gigabyte.com.tw/Products/Storage/Products_Overview.aspx?ProductID=2180

Weird...I thought the umem cards were more than just BBU SDRAM but...hmm...

> 
>> Software RAID is also good if you need to be able to transfer 
>> the disks 
>> to another box that does not have a hardware raid controller 
>> or the same 
>> controller.
>>
>> Weigh these in your decision. :-)
> 
> For 2 SATA hard disks used for the OS I think HW RAID is overkill.

Depends. HW RAID + BBU CACHE vs SW RAID vs SW RAID + NVRAM...You cannot 
say overkill in certain cases.

> 
> Besides I do not believe the PERC 5IR has BBU cache, that
> controller is really only meant as a simple RAID1 controller for
> the OS.

Dell certainly has a BBU cache option, not sure if OP's Poweredge box 
has that option.

> 
> If you use HW RAID you will need to install the manufacturer's
> software for monitoring it for a hard disk failure.

Yes, likely a negative but with Dell supporting Linux maybe not so.

> 
> If you wanted to add additional storage, say a SAS/SATA enclosure
> of 15 disks, then I would definitely invest in a HW RAID card for
> that!
> 

Depends :-D. How many hardware RAID cards offer 1GB of cache?



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