From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Feizhou
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...
Thanks, I'll have to give those bad boys a look-at.
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.
I only say that because if one is really looking for high performance then more spindles then 2 will be the first thing to do and getting that data off the OS drives that may do swap under load is key too.
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.
Oh yes, the PERC 5e is very good, I have a couple here and they really do pull in impressive numbers even with only 256MB write-back, I of course use these with the MD1000 enclosures though.
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.
Ah, well a lot of these are Java apps for cross-platform compatibility and some times the JavaVMs leak memory... so definitely YMMV.
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?
Not many I can tell you that, but then again a well implemented write-back cache doesn't need a huge amount of memory to be effective.
-Ross
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