- Community Home
- >
- Storage
- >
- Entry Storage Systems
- >
- Disk Enclosures
- >
- 'Normal' Raid 5 V's Online Spare
Categories
Company
Local Language
Forums
Discussions
Forums
- Data Protection and Retention
- Entry Storage Systems
- Legacy
- Midrange and Enterprise Storage
- Storage Networking
- HPE Nimble Storage
Discussions
Discussions
Discussions
Forums
Forums
Discussions
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
- BladeSystem Infrastructure and Application Solutions
- Appliance Servers
- Alpha Servers
- BackOffice Products
- Internet Products
- HPE 9000 and HPE e3000 Servers
- Networking
- Netservers
- Secure OS Software for Linux
- Server Management (Insight Manager 7)
- Windows Server 2003
- Operating System - Tru64 Unix
- ProLiant Deployment and Provisioning
- Linux-Based Community / Regional
- Microsoft System Center Integration
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Community
Resources
Forums
Blogs
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:13 AM
тАО01-15-2003 04:13 AM
'Normal' Raid 5 V's Online Spare
A quick question for you to ease my mind!
An ML570 (with Integrated Dual Wide Ultra 3 Controller) may be our next server, and to start with, we will purchase 4 x 36.4GB drives.
Do I use RAID 5 or RAID 5 with the online spare? With the spare I imagine I get a total capacity of 109GB (3 x 36) and a little bit extra re-assurance that the spare will kick in on disk failure.
Without the spare, do I get 145GB, and on disk failure, suffer a performance hit, while the data is rebuilt using the parity info?
Or have I not got it all!
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:35 AM
тАО01-15-2003 04:35 AM
Re: 'Normal' Raid 5 V's Online Spare
With a raid 5 set of 3 disks you get about 72GB capacity not 109. To get 109GB you need a Raid set of 4 drives, and if you want 1 online spare disk you need a total of 5 disks.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:42 AM
тАО01-15-2003 04:42 AM
Re: 'Normal' Raid 5 V's Online Spare
Usable space = (Total # of drives - spares -1) * 36
So, you have either:
usable space with spare = (4 - 1 -1) * 36 = 2*36 = 72
usable space no spare = (4 -0 -1 ) * 36 = 3 * 36 = 108
For me, I would use RAID 1/0 with 4 drives and no spare. You would get 72GB, it's faster, and you don't need a spare anyway. Keep a spare on the shelf if you are nervous about losing a drive.
Good luck,
Vince
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:43 AM
тАО01-15-2003 04:43 AM
Re: 'Normal' Raid 5 V's Online Spare
I will have 4 36GB drives, and according to the documentation I've read that's the minimun number of disks I need to use the online spare?
If I get you right, you are saying that using RAID 5, I'll get 109GB from 4 x 36's.
Dumbing it down a bit, what do I get from 4 x 36's using RAID 5 with the online spare?
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:45 AM
тАО01-15-2003 04:45 AM
Re: 'Normal' Raid 5 V's Online Spare
Two of us answered already: that would be 72Gb.
HTH,
Vince
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:48 AM
тАО01-15-2003 04:48 AM
Re: 'Normal' Raid 5 V's Online Spare
You'd get 3 disks used in RAID 5... so 1 for redundancy and the other 2 for data = 72Gb.
The other one will only be used when a disk fails, which would start the rebuild process automatically to it.
HTH,
Vince
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-15-2003 04:55 AM
тАО01-15-2003 04:55 AM
Re: 'Normal' Raid 5 V's Online Spare
Thanks Guys.
Could not see the sense in that at first, but I think I was looking for a more complicated answer than that what I got.
I get it now.
Thanks for your help.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО01-16-2003 12:08 AM
тАО01-16-2003 12:08 AM
Re: 'Normal' Raid 5 V's Online Spare
It look like you didn't get the exact principle of RAID5 and use of a spare (you should use "hot spare").
1) You will always suffer a performance hit when a disk fail.
2) You need at least 1 disk to be use for the parity of the RAID5. So, the highest capacity you can get is 109GB (3*36). Otherwise, on a disk fail, you loose all your datas.
3) "Hot spare" disk is a optional feature that will give you more security. With that disk online, the rebuild process start at once (even when your are sleeping at night...), so you don't spend time before changing the faulty drive(if a second disk fail before the end of the rebuilding of the first one, you loose all you datas). But, in this case you will have 2 disks used for redondancy and only 2 for storing datas (72GB). This should be used only for critical servers located on a distant location.
Michel