StorageSummit

Hybrid Storage Arrays
Storage experts discuss the pros & cons of hybrid storage arrays. Are they the best of both worlds?
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John Furrier
Question 2: 2) What hybrid storage array architecture delivers the best performance?
Dave Vellante
Speaking for @dfloyer I'd say those that were specifically designed to be hybrids and not bolt ons and I would add - those that persist to the flash directly
Jean-Luc Chatelain
Again I don't think it is an architecture per se (although important) but it is the SW intelligence driving the hybrid
Dave Vellante
The storage bottleneck in many workloads is very often de-staging the cache to the backend disk - a "Flash First" architecture (RAM first then flash) signals the write is complete when the flash has it then asynchronously trickles to disk
John Furrier
I ask this question on @theCUBE all the time and the responses are consistent .. "there will never be a tool that serves 100% of the market"
Jean-Luc Chatelain
If workload is 100% IOPS and small capacity then little value to hybrid and same if 100% streaming lots of large files but these are edge cases
Dave Vellante
Remember the original EMC Symmetrix? - the beauty of the architecture was it had a HUGE cache and mega backend disk bandwidth to de-stage the cache. Blew away the performance of everything out there. That was circa 1989 - pre-flash
Bert Latamore
while speed is important it is only one advantage of flash. There is also service level consistency and handling noisy neighbors for instance.
Jean-Luc Chatelain
A well designed hybrid should serve the bell of the curve well and differentiation between vendors should be flexible affinity to different host filesystems and applications
Kevin
de-staging is a huge issue when there is a backing-store cliff like #Exadata which is limited to 32,000 HDD IOPS. Datasheet: http://www.oracle.co...
Jean-Luc Chatelain
@dvellante Yes and the big delta between '89 and today is the economics
Kerstin Woods
@InformationCTO I think it's a combination - you need the right hardware (DRAM/flash size) to be useful AND you need intelligent caching algorithms to use it most effectively.
cmosoares
@InformationCTO Yep, cache was very expensive (in fact so were spinning disks) and of course no flash technology
cmosoares
@KerstinWoods In fact with ZS3 70-90% of I/O is server from extremely fast DRAM
John Furrier
Question 1: 1)What makes a storage array hybrid vs. a traditional array?
John Furrier
What makes a storage array hybrid vs. a traditional array?
Bert Latamore
Combination of flash and spinning disk
Dave Vellante
A hybrid uses a combination of spinning disk and flash. The nuance is that hybrids are designed to be hybrids versus a legacy array that bolts-on flash
Jean-Luc Chatelain
SW that intelligently adapt data placement and movement with appliance to the workload as opposed to fixed media type LUNS deferring to the apps to make decision
cmosoares
Hybrid storage arrays offer a combination of DRAM, flash memory and HDDs, featuring a cache-centric Flash-first architecture as Wikibon defines it
Dave Vellante
The other nuance (that we feel is important) is that the best value (at scale) comes from arrays that write directly to flash versus using the flash as solely a cache
Jean-Luc Chatelain
On right Hybrid apps should not see tiers but seamless persistence space which behave a maximum capability for varied workloads
Kerstin Woods
Important to note that not all hybrids are created equal. DCIG: Making the Right Hybrid Storage Buying Decision
http://bit.ly/1rEWXe...
Dave Vellante
Writes are the Achilles heel of storage arrays - writing to a persistent medium dramatically address write bottlenecks
Dave Vellante
@dfloyer modeled this effect - this chart shows iops at scale across different levels of write intensity http://wikibon.org/w...

Kerstin Woods
Similar in concept to hybrid cars - leverage one technology for cost savings and another for performance to gain the best of both.
Dave Vellante
You can see that even at 50% writes...at scale, the hybrid (flash first array) outperforms traditional arrays with MUCH lower write intensity.
Jean-Luc Chatelain
@dvellante But attention, not all writes are equal OLTP type writes sensitive to latency but OLAP or stream ingest write are about maximum throughput
Bert Latamore
Also with flash costs dropping the cost advantage of disk is decreasing.
Dave Vellante
@InformationCTO yes absolutely. In fact the ZFS array is best in high bandwidth apps (e.g. backup) and certain lighter weight analytics apps - NOT OLTP (to UR point)
cmosoares
@dvellante Following up on Dave and others Hybrids are designed as such from the beginning and also need intelligent SW to place data in the right storage tier. With the Oracle ZS3 we load up on DRAM (2TB) and Flash (23TB read/write)
John Furrier
@InformationCTO one thing that came up at #openstacksummit is the TCO piece of this discussion
Kerstin Woods
TCO is key. Looking at ZFS Storage hybrid vs traditional arrays over 4-years the ZS3 is 266% less expensive. Wikibon: ZS3 Reads for Show and Writes for Dough: http://bit.ly/1icydb...
cmosoares
Wikibon has written a report on how hybrid arrays are poised to disrupt traditional arrays due to performance and cost advantages. See it here i. http://bit.ly/RRgZVv...
Oracle Hardware
@Wikibon: Hybrid Storage is poised to disrupt traditional disk arrays: http://bit.ly/RRgZVv...
Oracle Hardware
Hello everyone and welcome to today's CrowdChat on Hybrid Storage Arrays!
John Furrier
great to be here
Oracle Hardware
Remember to enter your thoughts, questions and comments in the box at the top and vote for your favorite thread!
Dave Vellante
Looking forward to discussing hybrids and what we sometimes refer to as "Flash First" arrays