VSphere 5.5 and Virtual Flash Cache / Device - Do You Use It?
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@Nara said:
If you have 3 hosts, why not use vSAN? You'll get crazy IOPS, as well as have your data stored across multiple hosts.
That's definitely the way to go!
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It's using Cisco UCS that gets you. You give up the amazing performance of Dell or HP with things like CacheCade built in. All that unnecessary FCoE stuff to get out to the disk arrays.
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Does VMWare just know how to use CacheCade and other Caching tech to make your servers faster? or do you have to tell it how to set it up? Assuming the VM's are 100's of gigs in size, the Cachecade I'm guessing is only a few gigs, how does it decide what goes where?
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@Dashrender said:
Does VMWare just know how to use CacheCade and other Caching tech to make your servers faster?
CacheCade is at the physical storage layer, inside the RAID encapsulation the same as your normal NVRAM cache. VMware has no means of being aware of it. The same as it doesn't know how much RAM the controller has or how many disks are in your array. It just all appears as "an array."
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@Dashrender said:
Assuming the VM's are 100's of gigs in size, the Cachecade I'm guessing is only a few gigs, how does it decide what goes where?
NVRAM is normally 1GB+. CacheCade would rarely be under 200GB and could easily be 500GB.
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CacheCade is a cache, it decides what stays there in the same way that the RAID cache has always decided that and in the same way that the OS decides what to cache.
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@scottalanmiller said:
CacheCade is a cache, it decides what stays there in the same way that the RAID cache has always decided that and in the same way that the OS decides what to cache.
Awww.. Thanks for that! CacheCade is Dell, what does HP have?
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@Dashrender said:
@scottalanmiller said:
CacheCade is a cache, it decides what stays there in the same way that the RAID cache has always decided that and in the same way that the OS decides what to cache.
Awww.. Thanks for that! CacheCade is Dell, what does HP have?
CacheCade is LSI who makes for both.
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On the Dell side, be aware that you need the RAID controller with the 1GB NV RAM in order to enable cachecade on their servers. Both the H700 and H710P have the capabilities. Dell will tell you that you must use their SSD drives as the cachecade drives, but we have behnchmarked other SSD drives in our lab and verified that they work fine and achieve similar results.
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@Dashrender said:
@scottalanmiller said:
CacheCade is a cache, it decides what stays there in the same way that the RAID cache has always decided that and in the same way that the OS decides what to cache.
Awww.. Thanks for that! CacheCade is Dell, what does HP have?
Up to 4GB on-controller Flash-Backed Write Cache (FBWC) - unless I'm doing some extremely large data moves, it feels like I'm writing to flash, even under typical VM workloads.
