- Community Home
- >
- Storage
- >
- Midrange and Enterprise Storage
- >
- HPE EVA Storage
- >
- Re: Space savings of Vraid5 vs Vraid1
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
тАО12-14-2009 02:48 PM
тАО12-14-2009 02:48 PM
Space savings of Vraid5 vs Vraid1
If Vraid1's parity says that the entire size of the vdisk is mirrored, that means it's actually using 2.4TB of space on the array.
Now, if I was to change the vdisk from Vraid1 to Vraid5 and, knowing that the space overhead on Vraid5 is 25%, does that mean that the space used by this disk in Vraid5 configuration would be (in TB):
1.2+(1.2*0.25)
This is ~1.5TB, ignoring the 1000Gb vs 1024Gb topic for now. That's a 900GB saving if I was to change the vdisk from Vraid1 to Vraid5.
Is this correct? I'm not concerned with performance right now because EVAPerf tells me we're well under the available I/O for this particular disk group.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-14-2009 04:02 PM
тАО12-14-2009 04:02 PM
Re: Space savings of Vraid5 vs Vraid1
> This is ~1.5TB...
It is actually 20%. Vraid5 is using a 4D+1P model and it is based on blocks and not spindles. That is the 4D+1P are 4 data and 1 parity blocks that are spread on sets of 5 spindles at the time (but not the same 5 spindles but as many as the raid groups has in it). i.e the first set of 4D+1P blocks is using a set of 5 spindles, the second 4D+1P blocks is using a *different* set of 5 spindles and so on until all spindles in the groups are equially utilized and used up.
So it is really (1P)/(4D+1P) = 20% of your overall space.
I think the 25% is obtained based on the usable disk space, i.e. (1P) / 4D = 25%.
So, you should expect around 1.6TB of usable space. Now adding hot spare space complicates things a little bit because the hot spare space is still virtual and distributed to all disks but it is the equivalent to the space of 1 spindle.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-14-2009 05:03 PM
тАО12-14-2009 05:03 PM
Re: Space savings of Vraid5 vs Vraid1
So, the basic calculation I used makes the total used space for a 1.2TB vdisk in Vraid5 configuration ~1.44TB ... how did you arrive at 1.6TB?
Sorry, brain's not working today. :(
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-14-2009 06:45 PM
тАО12-14-2009 06:45 PM
Re: Space savings of Vraid5 vs Vraid1
If you assume 2.4TB of spindle space,
it is (2.4TB) * (0.8) = 1.92TB.
If you use sparing, you have to subtract the space of one spindle.
Either way it will much more than the vraid1 space.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-14-2009 06:51 PM
тАО12-14-2009 06:51 PM
Re: Space savings of Vraid5 vs Vraid1
I have a 1.2TB vdisk right now. 2.4TB is what I thought would be used in *spindle space* for a 1.2TB volume. Is that right?
Are you saying that Vraid5 will use more spindle space than Vraid1??
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-15-2009 01:47 AM
тАО12-15-2009 01:47 AM
Re: Space savings of Vraid5 vs Vraid1
a) 1,257GB Lun at Raid1
b) 2,011GB Lun at Raid5
c) 2,514GB Lun at Raid0
I realise you don't have this setup but the available space should still apply and hopefuly gives you a guide to what can be created with the available space.
Regards
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-15-2009 05:07 AM
тАО12-15-2009 05:07 AM
Re: Space savings of Vraid5 vs Vraid1
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-15-2009 11:48 AM
тАО12-15-2009 11:48 AM
Re: Space savings of Vraid5 vs Vraid1
They're all 15k FC but are not all the same size - a mix of anything from 72GB to 300GB as far as I know (EVA 8k which has been added to over the years).
For this reason I can't use StorageWorks SAN Sizer to do any calculations or estimates (gstonian I assume that's what you used to get those numbers?)
TTR, yes of course we have CV EVA (9.1) but which detailed info do you mean?
Thanks for all your answers so far, you are helping. :) Just not quite there yet ...
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-15-2009 12:02 PM
тАО12-15-2009 12:02 PM
Re: Space savings of Vraid5 vs Vraid1
Of course you can't use a simple formula when mixing disk drive sizes in a disk group. It depends on the exact (logical) position of the disks in a group how much space can be used on any particular disk drive. And this can easily change when disk drives are added or removed from the group.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО12-15-2009 12:03 PM
тАО12-15-2009 12:03 PM
Re: Space savings of Vraid5 vs Vraid1
500GB Vraid1 = 1GB used DG space
500GB Vraid5 = 600GB used DG space
100GB Vraid1 = 200GB used DG space
100GB Vraid5 = 120GB used DG space
These numbers, if correct, ignore sparing but I'm hoping they're reasonably close. It looks like I don't have those numbers correct though?
The whole point of all this is so that I can make recommendations to the customer about how much space we could save if we changed some of the low I/O Vraid1 vdisks to Vraid5.
Hopefully that additional info helps!