We help IT Professionals succeed at work.

We've partnered with Certified Experts, Carl Webster and Richard Faulkner, to bring you two Citrix podcasts. Learn about 2020 trends and get answers to your biggest Citrix questions!Listen Now

x

Fault tolerance

LFC1980
LFC1980 asked
on
Medium Priority
675 Views
Last Modified: 2010-04-03
This is a question from a MCSE book


You administer a server called Server1 which has a single physical disk that is configured as a simple volume

You plan to store the files for a large database on the server. You plan to install additional physical disks on the server

You need to configure the disks on the server so it provides fault tolerance for the operating system and the database files.

The answer says install 3 additional disks and create a new RAID-5 volume, and place the database files on the new volume

And

Install another disk and configure the simple volume as a mirrored volume


My question is: - Why three extra disks for the RAID-5,

And

Why do u need the Additional disk for the mirrored volume
Comment
Watch Question

3 is the minimum number for a RAID 5 array. Reason being that data is stripped across 2 disks and parity check bits are stored on the 3rd. In Theory if a disk fails then you can recreate the data from half the stripe and the parity. If Parity fails, you still have the data. In reality, this is short sighted and you should use more disks to provide faster recovery and hot standby disk to give zero impact in case of a failure. You can also stripe the parity across all drives to provide slightly better recovery.
You have no resilience in a single drive. Therefore, the mirror pair allows for a single drive to fail without impact.

Hope this helps.... or where you asking something else?
Barny

Not the solution you were looking for? Getting a personalized solution is easy.

Ask the Experts

Author

Commented:
ohhhhhhhhh

i get ya

the one that was in the machine will be used with the extra single one to make a mirror pair.

and the 3 extra will be for RAID 5....correct ?
Yes

Author

Commented:
Cool.

Thanks for confirming that, danhill85
Access more of Experts Exchange with a free account
Thanks for using Experts Exchange.

Create a free account to continue.

Limited access with a free account allows you to:

  • View three pieces of content (articles, solutions, posts, and videos)
  • Ask the experts questions (counted toward content limit)
  • Customize your dashboard and profile

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

OR

Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.