On 10/27/11 23:52, Eric Shubert wrote:
On 10/26/2011 09:07 PM, Pak Ogah wrote:
On 10/27/11 10:24, Casey wrote:
On 10/26/11 7:55 PM, Eric Shubert wrote:
On 10/26/2011 06:44 PM, Casey wrote:
....
Also, what are you using as a
RAID controller? Hardware, Linux, fakeraid?
Linux software raid. No special hardware controller, just straight
through devices.
These 2560's have PERC3/Di controllers - 128MB RAM, and a battery
backup...is a Linux software RAID a better option? Performance?
Reliability?
My 2,000 Rupiahs, :D
Hardware Raid controller with amount of memory and Backup batery is much
more better than Software.
I only use software raid, if I don't have the controller and want data
redundancy.
I disagree.
Let me begin by saying that if you run raid-5, you'll likely need a
hardware raid solution (not fake raid) in order to handle the cpu
requirements. Raid-5 also can give improved read performance with
many,many drives. That's not a typical scenario though.
With raid-1 or raid-10, there's not enough of a processing requirement
to warrant extra hardware. The main CPU can handle it just fine, and
the hardware raid won't buy you much (freeing up cpu cycles).
With a QMT host, disk performance is probably not going to be your
limiting factor, so I wouldn't be very concerned about performance of
one configuration vs another, so long as you don't need to use raid-5
for whatever reason. If you decide that you must use raid-5, use a
hardware controller for it. I must say though, that I (strongly)
recommend avoiding raid-5 whenever possible.
The big problem I have with hardware raid controllers is that they use
proprietary methods to store the data on disk. When a raid controller
goes bad (and they do), you *must* have an equivalent controller in
order to access the raid array. That's a position I like to avoid
being in. If it's a card that's no longer available, you better have a
couple (that you know work) sitting on the shelf just in case.
On the other hand, with software raid, I can access and recover data
from the drives quite easily with any ol' commodity hardware.
BL, hardware raid controllers are only beneficial with raid-5, which I
don't use or recommend. Give me software raid any (and every) day.
thank you for the insight Eric,
the reason why I am suggesting Hardware raid are (based on my experience):
- I got branded server (HP) from company, and by default the vendor
always ship it with raid controller (P212/P400)
- since the servers got 3 years warranty, and my company and vendor
already have long business relation, so I do not have to worry, if
existing controller broken, I am sure the vendor will help me (so I
don't have to spare a controller on my shelf)
- raid controller is make me easy changing harddrive (hot-swap)
- after 10 years, only 1 of 20 servers that have broken the controller,
and that is and old server (bought at 2002), we replace it already.
- hardware raid controller is supported by vmware vsphere/hypervisor
- once I had problem converting a linux with software raid 1 into vm
using vmware vconverter, so I have to reinstall the OS/apps again :(
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