Storage – Strip Unit Size

Background

A Storage disk’s Strip Unit Size is often taken into consideration as one considers storage alignment.

So I am finishing up and closing all opened Google’s Chrome Tab, and went back and read:

Disk Partition Alignment (Sector Alignment) for SQL Server: Part 4: Essentials (Cheat Sheet)
http://blogs.msdn.com/b/jimmymay/archive/2008/12/04/disk-partition-alignment-sector-alignment-for-sql-server-part-4-essentials-cheat-sheet.aspx

Jimmy May’s paper principally deals with Microsoft products: SQL Server on Windows OS, but his formula is very generalized.

 

Strip Unit Size – What does it matter?

Let us see how it plays out:

Here is Jimmy May’s formula:

Three Values - Two Essential Correlations

Jimmy’s document says:

  • Perform these calculations for each partition which must result in integer values
  • Of the two, the first is far more important.  Use the information below to divine this information.

And, here is how he says to get “File Allocation Unit Size” and also “Starting Offset”:

GetJimmysNumbers

It is left to the inquiring mind how to get “Stripe Unit Size” as that number is not based on the OS, Microsoft Windows, in this case; but based on the Vendor and each Application.

Matrix – Vendor

Here are some numbers for various vendors and models:

Strip Unit Size
Vendor Model# Strip Unit Size
EMC Clarion  64k
NetApp (all models)  4k
HP (all models)  64k -to- 256k

Matrix – Application

Here are popular applications along with their Block Size.

Block Size
Vendor Application Block Size
Microsoft SQL Server  64 kb
Hadoop HBASE  64 kb
MySQL\Percona InnoDB  512 Bytes

Matrix – Application – MySQL/Inno DB

http://www.percona.com/doc/percona-server/5.5/scalability/innodb_io_55.html?id=percona-server:features:innodb_io_55

This variable changes the size of transaction log records. The default size of 512 bytes is good in most situations. However, setting it to 4096 may be a good optimization with SSD cards. While settings other than 512 and 4096 are possible, as a practical matter these are really the only two that it makes sense to use. Clean restart and removal of the old logs is needed for the variable innodb_log_block_size to be changed.

Calculation

Calculation – NetApp

  1. NetApp’s default Strip Unit Size is 4K and Microsoft’s SQL Server best practice suggest using a File Allocation Unit Size of 64K.
  2. It does not take much calculation to deduce that 4K / 64K will not render an integer value, but a fractional value
  3. Please keep in mind that for NTFS, the default Strip Unit Size is 4K and one will get a whole number of 1 (Strip Unit Size / File Allocation Unit Size = 4 K / 4K = 1)

References

References – Vendor – Microsoft

References – Vendor – NetApp

References – Vendor – EMC

References – Vendor – HP

References – Vendor – Oracle

References – Vendor – MySQL

References – Technology – Hadoop

References – Changing Block Size

Technical: NetApp – MPIO – Path Details

Technical: NetApp – MPIO – Path Details

As part of NetApp diagnostic, you might need to dig deep into which paths are actually being used.

MPIO Path Details

  1. Launch Computer Management
  2. In the left panel, Access Storage \ Data OnTap(R) DSM Management \ Disk Management
  3. In the right panel, select the Disk
  4. Right Click on the the Disk Nth, and in the ensuring “Drop-down” menu, select the “Properties”
  5. The “NETAPP LUN Multi-Path Disk Device Properties” window appears
  6. The paths are listed in the “This device has the following paths”
  7. Double-clicked on the path you want to dig into …
  8. The “MPIO Path Details” window appears

NetApp - MPIO Path Details

The following areas are displayed:

  • Number of Reads
  • Number of Writes
  • Bytes Read
  • Bytes Written

 

Note that in the instructions above, you can not select the “Logical Disk”.

 

Computer Management

 

So in the screen above, please select “Disk 4” and right click on that selection.

 

NetApp – nSanity

NetApp – nSanity

http://support.netapp.com/NOW/download/tools/nsanity/

nSANity Data Collector is a support tool designed to aide users and technical support in troubleshooting complex issues. nSANity is able to collect diagnostic and configuration data from a variety of components including:

To get it, you need a NetApp account.

Here are a couple of usage documentation.



Syntax:

    nsanity windows:[domain-name]\[user-name]:*@[host-name]

Sample - connect to local computer, using current user's credentials

   nsanity windows://localhost

Sample - use current user's credentials

   nsanity windows://dbHR

Sample (enter password in clear text)

   nsanity windows://corp\daniel:mypwd@dbHR

Sample (enter password when prompted)

   nsanity windows://corp\daniel:*@dbHR

There are some important details when you run this on a MS Windows platform and target a MS Windows host.  Here they are:

  • If you enter credentials and target your current machine, ensure that the username and password are correct; as things will not work otherwise.  Even though, this requirement must be met you will subsequently be told “User credentials can not be specified for local connections, retrying with current user credentials
  • Based on one the comments posted by a user, the password entered can not be more than 8 characters. I can confirm that as version 1.2.10 that is no longer the case.

On MS Windows Host:

On MS Windows host, please make sure that you have the following installed:

http://updates.mistral.net/netapp/Tools/nsanity/nsanity_userguide.pdf

MFC90 – Requirement

The Windows executable requires MFC90 Runtime libraries, which are included with Windows 7. If your Windows host does not have the required libraries then they may be downloaded from Microsoft at the following URL.

MFC 90 is bundled with Microsoft Visual C++ 2008 SP1

FCINFO for Windows 2003

Microsoft Windows 2003 hosts require an additional package in order to allow complete data collection of HBA information. The Microsoft package is call fcinfo, which provides the HBAFAPI and WMI classes to access the API.

This package may be downloaded directly from Microsoft:

http://www.microsoft.com/downloads/details.aspx?familyid=73d7b879F
55b2F4629F8734Fb0698096d3b1&displaylang=en

References: