svc / storwize: cost effective storage planning (bvq use case)

Find most economic disk setupwith BVQ

Bsys2.pptx

Michael Pirker

[email protected]

+49 151 180 25 26 00

Target for this presentation

• Target

• a mail environment has to be moved from an oversized 10k 300GB storage to a new

storage environment. The new environment shall use 7.2k 1TB drives with Raid 6.

• BVQ is already installed so we can measure IOPS, RW Distribution and caching to do

a most economic sizing

• We analyze the performance of all disks that are involved

• We can proof that 2500 IOPS are what we need

• It is already known that R/W distribution is 55% Read

• The diagram shows a constant read cache hit rate of 90%

• The diagram shows a constant write cache hit rate (overwite in cache) of 15%SVC will put all write data on the cache but 15% of this data will be overwritten before destaging happens. These IOPS will never affect the disk.

• Safety Margins We see a transfer rates which will improve write penalties for raid 6. ánd we use a conservative IO estimation for 7k drives. We do not take in account that the storage system may further improve IO behavior with of own caching

Select Volumes for performance analysis

Make use of the BVQ Accounting Package

� Create a Volume Group of all Volumes that belong to the mail system� Analyze the Volume Group now

Without Accounting Package you can select all volume by search.

Facts measured to support calculation

• Requested

• 40 TB Capacity

• 2500 IOPS

• Facts from Chart (4 work days)

• 55% RW Distribution

• 90% Cache Hit Read

• 15% Cache Hit Write

• Big Transfer size improves “Write Penalty” for Raid 6 (Full Striped Writes)

Cache Hit Read

Cache Hit Write

IOPS RW

Transfer Size RW

Results with Spreadsheet• Target IOPS 2500 IOPS

• RW Distribution: was measured before. Splits IOPS in

R/W

• Cache Hit Read: Reduces read IOPS with measured

Cache Hit Rate

• Cache Hit Write Reduces write IOPS (Overwrite in

Cache ) with measured Cache Hit Rate

• IOPS eff. is sum of read IOPS

and write IOPS

• The number of disks are now calculated with this formula

Result is 48 Disks with 7.2kRPM

Good fit because we need 40TB capacity

What makes this result particularly valuable?

• calculated based on facts

� decreased the number of needed Disks dramatically

• most economic result

• minimum of costly safety margin

Other scenarios without knowledge about facts

We assume Raid 6 and 50% read and 70% cache hit for read

� IOPSeff = 1625 � 72 Disks

We assume Raid 6 and nothing more

� IOPSeff = 2500 � 201 Disks

BVQ in the www

• BVQ Website http://www.bvq-software.com/ (still German will change to English until latest Feb 25. 2013)http://www.bvq-software.de/ (German)http://bvqwiki.sva.de (technical wiki with download – international)

• BVQ Videos on YouTubehttp://www.youtube.com/user/SVAGmbH

• SVA Webseite von SVA GmbH http://www.sva.de/

Internationale Webseiten

• Developer Works Documents and Presentationshttps://www.ibm.com/developerworks/mydeveloperworks/...

http://tinyurl.com/BVQ-Documents