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Asset ID: 1-71-1011237.1
Update Date:2011-05-11
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Solution Type  Technical Instruction Sure

Solution  1011237.1 :   Sun StorageTek[TM] 5000 Series NAS: Verifying Backend Storage Performance from the NAS CLI  


Related Items
  • Sun Storage 5210 NAS Appliance
  •  
  • Sun Storage 5220 NAS Appliance
  •  
  • Sun Storage 5310 NAS Appliance
  •  
  • Sun Storage 5320 NAS Gateway/Cluster System
  •  
  • Sun Storage 5320 NAS Appliance
  •  
  • Sun Storage 5310 NAS Gateway System
  •  
Related Categories
  • GCS>Sun Microsystems>Storage - Disk>Network Attached Storage
  •  

PreviouslyPublishedAs
215434


Description
This document describes how CLI commands can be used to measure read/write performance on the backend disk storage on a Sun StorageTek[TM] 5000 Series NAS.



Steps to Follow
When working on performance issues, there may be a need to verify the operation and/or performance of the backend storage. For example, if network performance is slow, it is often wise to check the backend performance to isolate the source of the problem to the server or the storage. The following commands are used for this purpose: aratewrite and rateread.

To access the CLI on OS version 4.21 or later, simply open a telnet or ssh connection to the NAS and enter the administrator password. For version 4.20 and earlier, first enter admin in response to the "[menu]" prompt.

NOTE: Running these CLI commands can impact the performance of the array. Ensure that the customer is aware of this before attempting to run these commands.

Aratewrite

The aratewrite command is used to create a file, and will return performance data after the write operation is complete. The syntax for this command is as follows:

 aratewrite /volume/directorypath/filename size blocksize

Volume and directorypath make up the full path to the destination file. The specified filename will be created in the specified location. The size is the size of the file to be created in kilobytes. So a file of size 1000000 would be 1 gigabyte is size. Before running this, the customer should verify that sufficient free space exists to create the file. A blocksize of 32768 should be used for performance testing, though this parameter can be varied. The default block size is 8K.

The following example shows the syntax for an aratewrite creation of approximately a 10G file:

 NAS > aratewrite /vol1/test.file 10000000 32768
Writing 9765MB in 32KB blocksize with 0MB per commit.
10240000000 bytes (9.536G) in 188.415 seconds  51.83MB/sec

This was taken from a completely idle ST5320. Performance can vary widely based on the model, storage configuration and what the server is doing at the time.

Be sure to delete any files created with aratewrite when finished testing. A console del command is available for this purpose.

Rateread

The command rateread is used to read a file and will give performance at the end of the file read operation. It uses the following syntax:

 rateread /volume/directorypath/filename blocksize

As above Volume and directorypath make up the full path to the destination file, and filename is the name of the actual file to be read. Once again the 32768 blocksize should be used. It is very important to use actual data files and NOT the files created by aratewrite or ratewrite for this purpose. These file contain repeating simple patterns and will return artificially high results, due to caching.

Here is an example of rateread output from the same 5320:

 rateread /vol2/bigfile.cap 32768
10737418240 bytes (10G) in 64.960 seconds  157.6MB/sec

Evaluating Results

It is very important to note that these commands are intended as a sanity check for the backend performance, and to isolate performance problems. Actual benchmarking should involve multiple clients moving continuous streams of data to and from the NAS over the network.

When measuring performance with these utilities, compare the network performance to the ratewrite results for clues where to look for a problem. For example, if you are copying a file from the NAS at 500KB/s and rateread shows 60M/s that would be an indication to look elsewhere. However, if rateread returned a similar result, you could look into disk related solutions such as cache or non-optimal LUN status.

Below are some examples of the different commands run on a 5310 and a 5210. Also included are examples of commands run on a 5210 that has a cache battery problem, showing how the write performance is impacted. All 3 of these arrays were idle as far as front end activity so these numbers reflect that.

Example of commands run on a 5310:

 SE5310 > aratewrite /PTStestvol01/testfile1gb 1000000
Writing 976MB in 8KB blocksize with 0MB per commit.
1024000000 bytes (976.5M) in 36.619 seconds  26.66MB/sec
 SE5310 > aratewrite /PTStestvol02/testfile1gb 1000000
Writing 976MB in 8KB blocksize with 0MB per commit.
1024000000 bytes (976.5M) in 35.779 seconds  27.29MB/sec
 SE5310 > aratewrite /PTStestvol03/testfile1gb 1000000
Writing 976MB in 8KB blocksize with 0MB per commit.
1024000000 bytes (976.5M) in 37.470 seconds  26.06MB/sec

Example of commands run on a normal 5210:

 se5210-146g-a > aratewrite /vol01A/testfile1gb 1000000
Writing 976MB in 8KB blocksize with 0MB per commit.
1024000000 bytes (976.5M) in 11.153 seconds  87.55MB/sec

Example of commands run on a 5210 with a cache battery problem:

 v-se5210a > aratewrite /vol01A/testfile1gb 1000000
Writing 976MB in 8KB blocksize with 0MB per commit.
1024000000 bytes (976.5M) in 341.185 seconds  2.861MB/sec


Product
Sun StorageTek 5210 NAS Appliance
Sun StorageTek 5310 NAS Gateway/Cluster System
Sun StorageTek 5310 NAS Gateway System
Sun StorageTek 5320 NAS Gateway/Cluster System
Sun StorageTek 5320 NAS Appliance
Sun StorageTek 5320
Sun StorageTek 5310 NAS Appliance
Sun StorageTek 5220 NAS Appliance
Sun StorageTek 5220

Internal Comments
This document contains normalized content and is managed by the the Domain Lead(s) of the respective domains. To notify content owners of a knowledge gap contained in this document, and/or prior to updating this document, please contact the domain engineers that are managing this document via the “Document Feedback” alias(es) listed below:

storage-nas-domain@sun.com


The Knowledge Work Queue for this article is KNO-STO-NAS
Storedge, nas, 5210, 5310, 5320, performance, rateread, aratewrite, cli, audited
Previously Published As
85468

Change History
Date: 2007-10-01
User Name: 7058
Action: Approved
Comment: OK to publish. No further edits required.
Version: 6
Date: 2007-09-28
User Name: 7058
Action: Accept
Comment:
Version: 0

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