Upgrading to Dell Poweredge T440 - Raid 1 + Raid 5 Help HDs

JReam
JReam used Ask the Experts™
on
My small business is getting a Dell Poweredge T440 and we were advised to use Raid 1 for the OS and Raid 5 for the other drives.

We are going to get 8, 3.5 inch slots for HDs. OS will use 2 drives and Raid 1. Then we want 4 drives to be set up with Raid 5.

Does this give us 4 drives and 2 "hot spares"?
Comment
Watch Question

Do more with

Expert Office
EXPERT OFFICE® is a registered trademark of EXPERTS EXCHANGE®

Commented:
It could.  Does Dell support global hot spares, one spare drive for both arrays or one spare for each array...
I would if supported go with a global hot spare and take the other "spare drive " and add it to the raid 5 disk.

Commented:
What PERC (Dell Array controller) was purchased with the server?

Author

Commented:
H730P
Ensure you’re charging the right price for your IT

Do you wonder if your IT business is truly profitable or if you should raise your prices? Learn how to calculate your overhead burden using our free interactive tool and use it to determine the right price for your IT services. Start calculating Now!

Commented:
This Perc supports both types of hot "Global and dedicated hot spare with revertible hot-spare support: automatic rebuild, enclosure affinity,
emergency SATA"

see:
https://i.dell.com/sites/doccontent/shared-content/data-sheets/en/Documents/Dell-PowerEdge-RAID-Controller-H730P.pdf

Hot spare configuration, Dell:
https://www.dell.com/support/manuals/ca/en/cadhs1/poweredge-rc-h830/perc9ugpublication/managing-dedicated-hot-spares?guid=guid-ffb8d4c0-3925-4f92-8dca-7ee6bb469d0d&lang=en-us
Distinguished Expert 2017

Commented:
You might want to consider using RAID 6 instead of RAID 5
2 raid 1 for OS Space based on 1 disk
5 DISKS for RAID 6 Space is 3xsize of disk
1 global hot spare.
Though a spinning drive even if not accessed can go bad, it might be better to have the one drive on hand and not in the system unless and until you get a warning that a drive is having issued.


Without knowing for what purpose the system is being setup,

Author

Commented:
Thanks for the information guys.  I realized I was off in my initial post. I want a net of 4 Drives so with RAID 5 I would need 5 drives (4 net drives, 1 parity). This would leave me with 1 "hot spare".

If I configured this with RAID 6 would that mean in order to get 4 net drives I would need to have 6 drives setup for RAID 6 (4 net, 2 parity)? Would this option effectively leave me with no "hot spares"?

Commented:
Correct RAID 6 requires to 2 parity discs, RAID 6 can tolerate 2 drive failures.  I prefer a hot spare and alerting.

Author

Commented:
Thanks again for helping me wrap my head around RAID 1+  RAID 5 / RAID 6
Andrew Hancock (VMware vExpert / EE Fellow)VMware and Virtualization Consultant
Fellow 2018
Expert of the Year 2017

Commented:
Dell no longer consider RAID 5 as suitable for Enterprise Computing!


go with RAID 6.
Distinguished Expert 2017

Commented:
What size drives are we talking about?
Raid 5 rebuild following a drive failure takes a while depending on the drive size, during that time a se obj drive failure (due to higher load) would bring down the array.

A performance hit is significant.

What will be residing on the raid 5 volume?
https://www.zdnet.com/article/why-raid-5-still-works-usually/

https://www.zdnet.com/article/why-raid-5-still-works-usually/
Top Expert 2014

Commented:
SFF chassis may make more sense, then you get 16 drive bays rather than 8. Of course you can't have huge capacity drives but it's those high capacity drives that you really do need RAID 6 for. Only costs about €50 to get 8 extra bays*. The low capacity 3.5 inch ones are 2.5 inch anyway internally, e.g. "2.4TB 10K RPM SAS 12Gbps 512e 2.5in Hot-plug Hard Drive, 3.5in HYB CARR " from the customize it option on Dell's site.

*plus the cost of the extra disk.

Do more with

Expert Office
Submit tech questions to Ask the Experts™ at any time to receive solutions, advice, and new ideas from leading industry professionals.

Start 7-Day Free Trial