Main > Everything Else

Raid 5 guestions??

<< < (11/12) > >>

patrickl:

--- Quote from: meismr on February 03, 2008, 06:59:43 pm ---Fair enough, we don't agree.  I didn't misread your post.  You were wrong.  I said enterprise solutions separate their OS and data drives.  I'm right. 
--- End quote ---
You missed the point again. You said that there is no need to mirror the OS drive. An enterprise solution never has an OS disk that isn't (at least) mirrored.

I only asked you to explain why you felt it that important to separate the OS and data that you would even destroy the redundancy of the system just to achieve this separation. That doesn't mean I disagree with separation. I just think that redundancy is the key in a redundant system, while you seem to think that ease of OS installation by swapping disks is what's more important.


Anyway, talking about a truly massive enterprise solution, see the Google drive failure analysis (PDF). I found it pretty informative. Surprising too since they state that drive temperature didn't seem to matter much.

They also say that SMART errors don't always warn ahead of disk failures/errors. Still a pretty high percentage is predicted. It's good to check the logs for those or have them e-mailed to you.

squirrellydw:
agree to disagree or agree, I don't care.   I get the point you are both trying to make and I appreciate all your comments and suggestions.  I am going to start with 3 drives in a raid 5 then go to a raid 6 then add a hot spare.  The OS will be on a separate drive.

Any other suggestions??

boykster:
I know I said it before, but it deserves re-stating:

buy a good power supply. 

single most important component in a large disc array, even more so than the controller.  A super expensive controller card with a crappy PSU will be less reliable than a bunch of disks in JBOD using software paired with a high quality PSU.

patrickl:

--- Quote from: boykster on February 03, 2008, 11:45:01 pm ---I know I said it before, but it deserves re-stating:

buy a good power supply. 

single most important component in a large disc array, even more so than the controller.  A super expensive controller card with a crappy PSU will be less reliable than a bunch of disks in JBOD using software paired with a high quality PSU.


--- End quote ---
Indeed. I've had at least three PSU's die on me (in workstations though). Although oddly enough those were actually quality PSU's.

I ran a HP Netserver LH3000 as file RAID server and it actually had redundant power supplies. That was a cool machine. Unfortunately it made more noise (and wind) than two vacuum cleaners too  :P

Don't underestimate the failure rate of hard drives used in a 24/7 application. If you read the manufacturers specs you'd expect a drive failure rate of 1% (for enterprise quality disks) and 3% (for consumer grade disks). Unfortunately in real life studies (like the Google study I pointed to earlier) they report annual failure rates of 6% and up to 12%.

Also check the warranty. I always return a broken disk if it breaks within the warranty period. Keep the box that you received the disks in, because they often have strict rules about the packaging of returned disks. I found that I often get a bigger disk back than what I returned. In one case I had to pay an administration fee (Seagate). A few months ago I returned two disks that started showing SMART errors and I got new ones for those too.

Also think about wether you want to spin down the drives or not and think about using enterprise disks (which are specifically designed for 24/7 RAID solutions) as opposed to consumer grade disks (which are designed for 8/5 office hour applications).

squirrellydw:
OK, a few more questions now.

What is JBOD
What is considered an enterprise disk
what do you mean by spin down the drives

Thanks

Navigation

[0] Message Index

[#] Next page

[*] Previous page

Go to full version