Feeds

Microsoft flash research inspires EMC

Data Domain flash-based dedupe coming

Next gen security for virtualised datacentres

EMC is using Microsoft research into flash use as a memory tier between DRAM and disk drives to speed up Data Domain deduplication.

FlashStore is a Microsoft research project that batches up flash writes in a server's main memory and then writes them as a page or block, in effect turning random flash writes into sequential ones and avoiding block erase/write cycles that are otherwise endemic to flash.

Such cycles both slow down flash writes and can shorten its working life by increasing the number of block erase/write cycles in a time period, flash blocks having a finite erase/write cycle capacity.

The Microsoft researchers Sudipta Sengupta, Jin Li and intern Biplob Debnath said FlashStore minimises its DRAM footprint by using an index to access the data in the flash cache.

This is a key:value store using a hash-table index. Microsoft tells us it saves space on both the vertical and horizontal dimensions of the table by using a version of cuckoo hashing - where keys in table slots serve as eggs pushed out of the nest - to reduce the number of slots and slot sizes in the hash table.

In cuckoo hashing, as we understand it, for any key value two hash functions are used instead of one, giving the key two possible locations in the table instead of one. Any pre-resident key in that slot is booted out and it is then put in its alternative slot, booting out any already resident key until an empty slot is found.

Apparently this saves up on lookup time, with just two slot inspections needed. But the table has to be less than half full and, if it gets full, it has to be rebuilt because there isn't an empty slot for the last displaced key value hash.

Returning from computer science territory

The researchers say that the FlashStore DRAM table is frugal in its use of DRAM and provides fast access time with an average of a single flash read per lookup. This means servers using it can perform many times faster; "several tens of factors of increased data throughput" is the phrasing they use.

Sengupta says this about applications with high IOPS needs: "You could replace 10 to 20 hard drives with one flash drive using FlashStore for such applications.

"That gives you a capital-expenditure savings, power savings, and operational-expenditure savings, as well, and you also get much faster throughput: an all-win situation on the three metrics of price, power, and performance.”

Deduplication

It sounds like deduplication could use this technique. Microsoft's FlashStore paper says: "FlashStore also achieved significantly better results than a RAM/hard drive or a flash drive when tested with the task of performing data-chunk indexing for data deduplication."

Secure remote control for conventional and virtual desktops

More from The Register

next story
HP busts out new ProLiant Gen9 servers
Think those are cool? Wait till you get a load of our racks
Shoot-em-up: Sony Online Entertainment hit by 'large scale DDoS attack'
Games disrupted as firm struggles to control network
Community chest: Storage firms need to pay open-source debts
Samba implementation? Time to get some devs on the job
Like condoms, data now comes in big and HUGE sizes
Linux Foundation lights a fire under storage devs with new conference
Silicon Valley jolted by magnitude 6.1 quake – its biggest in 25 years
Did the earth move for you at VMworld – oh, OK. It just did. A lot
Forrester says it's time to give up on physical storage arrays
The physical/virtual storage tipping point may just have arrived
prev story

Whitepapers

5 things you didn’t know about cloud backup
IT departments are embracing cloud backup, but there’s a lot you need to know before choosing a service provider. Learn all the critical things you need to know.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Backing up Big Data
Solving backup challenges and “protect everything from everywhere,” as we move into the era of big data management and the adoption of BYOD.
Consolidation: The Foundation for IT Business Transformation
In this whitepaper learn how effective consolidation of IT and business resources can enable multiple, meaningful business benefits.
High Performance for All
While HPC is not new, it has traditionally been seen as a specialist area – is it now geared up to meet more mainstream requirements?