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Cleanur
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7 months ago
in Grapples and Tangelos: Why it’s Impossible to Compare Fairly on Stephen Foskett, Pack Rat
There are very few similarities between the CX and EVA architecture, the only part that comes even close to being comparable is how they are physically put together, i.e dual controllers and multiple enclosures, the similarities end there. In terms of how the system is managed, and how functionality is implemented, the two are completely different animals.
Here's some numbers for the EVA, BTW I don't work for HP but do like the EVA technology. Once you've used it's a bit like a good sat nav (EVA) after using a paper map atlas (traditional array) all your life. Initially you completely mistrust where it's taking you and try to go your own way, over time your mistakes become more appernt and you learn to trust the technology.
Equivalent of 120x146GB = 17.5TB required total usable (inc Raid 5 + Sparing)
Single DIsk group (all VR5 as per Chuck)
173x146GB = 25,258GB RAW
173x146GB = 24,666GB after Rightsizing
173x146GB = 23,643GB after Metadata
Set 90% occupancy alarm = 10% reserve = 21,279GB
Add distributed sparing = 21,033GB
Vraid 5 available = 17,527GB
% Available = 17,527GB / 24,666GB = 71% utilization
173 Disks = 13 Enclosures
A more realistic config for a large Exchange environment would be.
Two DIsk groups (all VR5 as per Chuck)
144x146GB = 21,024GB RAW
144x146GB = 20,531GB after Rightsizing
144x146GB = 19,680GB after Metadata
Set 90% occupancy alarm = 10% reserve = 17,712GB
Add distributed sparing = 17,466GB
Vraid 5 available = 14,555GB
% Available = 14,555GB / 20,531GB = 70%
Disk group 2 = 32x144GB = 4672GB RAW
32x144GB = 4,562GB after Rightsizing
8x144GB = 4,373GB after Metadata
Set 90% occupancy alarm = 10% reserve = 3,936GB
Add distributed sparing = 3,690GB
Vraid 5 available = 3,075GB
% Available = 3,075GB / 4,562GB = 67%
70% + 67% = 137 / 2 Disk groups = 68.5% utilization
144 Disks + 32 Disks = 176 = 13 Enclosures
14,555GB + 3,075GB = 17,630GB
Note these are real world figures without vendor spin. A key thing about the use of disk groups and vdisks is that of the 17.xTB available on each configuration, every GB displayed as usable, is absolutely usable within the disk group i.e No stranded capacity within the stripe set as is usually the case for a non virtualized array. I know from experience that with a traditional array environment, over time you tend to create pockets of stranded space all over the array with little chance of reclamation, unless your predictions and planning are spot on. With virtual pool you just take the capacity required at any point in time, you've divorced capacity from the underlying pool so when you need some more just take it. Not enough space in the pool, just add some more and draw the capcity you need. It's all on line and totally transparent to the hosts and applications. HP have had technology for 6+ years now but have failed to market the benefits to there full potential.
Here's some numbers for the EVA, BTW I don't work for HP but do like the EVA technology. Once you've used it's a bit like a good sat nav (EVA) after using a paper map atlas (traditional array) all your life. Initially you completely mistrust where it's taking you and try to go your own way, over time your mistakes become more appernt and you learn to trust the technology.
Equivalent of 120x146GB = 17.5TB required total usable (inc Raid 5 + Sparing)
Single DIsk group (all VR5 as per Chuck)
173x146GB = 25,258GB RAW
173x146GB = 24,666GB after Rightsizing
173x146GB = 23,643GB after Metadata
Set 90% occupancy alarm = 10% reserve = 21,279GB
Add distributed sparing = 21,033GB
Vraid 5 available = 17,527GB
% Available = 17,527GB / 24,666GB = 71% utilization
173 Disks = 13 Enclosures
A more realistic config for a large Exchange environment would be.
Two DIsk groups (all VR5 as per Chuck)
144x146GB = 21,024GB RAW
144x146GB = 20,531GB after Rightsizing
144x146GB = 19,680GB after Metadata
Set 90% occupancy alarm = 10% reserve = 17,712GB
Add distributed sparing = 17,466GB
Vraid 5 available = 14,555GB
% Available = 14,555GB / 20,531GB = 70%
Disk group 2 = 32x144GB = 4672GB RAW
32x144GB = 4,562GB after Rightsizing
8x144GB = 4,373GB after Metadata
Set 90% occupancy alarm = 10% reserve = 3,936GB
Add distributed sparing = 3,690GB
Vraid 5 available = 3,075GB
% Available = 3,075GB / 4,562GB = 67%
70% + 67% = 137 / 2 Disk groups = 68.5% utilization
144 Disks + 32 Disks = 176 = 13 Enclosures
14,555GB + 3,075GB = 17,630GB
Note these are real world figures without vendor spin. A key thing about the use of disk groups and vdisks is that of the 17.xTB available on each configuration, every GB displayed as usable, is absolutely usable within the disk group i.e No stranded capacity within the stripe set as is usually the case for a non virtualized array. I know from experience that with a traditional array environment, over time you tend to create pockets of stranded space all over the array with little chance of reclamation, unless your predictions and planning are spot on. With virtual pool you just take the capacity required at any point in time, you've divorced capacity from the underlying pool so when you need some more just take it. Not enough space in the pool, just add some more and draw the capcity you need. It's all on line and totally transparent to the hosts and applications. HP have had technology for 6+ years now but have failed to market the benefits to there full potential.
