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Host Configuration Guide IBM AIX  AIX  SANsymphony-V June 2015

Global Leader in Storage Virtualizati Virtualization on Software

 

  Table of contents Overview Recent changes made to this document

List of qualified AIX Versions

3  3



Notes on qualification qualificati on

4

AIX

5

DataCore Server Settings



AIX 5.2

6

AIX 5.3

6

AIX 6.1 and 7.1

6

Host Settings Applies to any AIX Host

Appendix A Notes on the Preferred Server & Preferred Path settings

Appendix B

9  9

11  11

13 

Configuring Disk Pools

13

Reclaiming Storage from Disk Pools

13

Previous Changes 

15

 

 

Overview This document provides AIX-specific settings when serving Virtual Disks from a DataCore Server. Fundamental AIX administration skills are assumed; including how to connect AIX Hosts to storage array target ports (i.e. DataCore Server Front End ports) using Fibre Channel, along with the process of discovering, mounting and formatting disk devices in general. Note: iSCSI connections from AIX are not currently currently supported

Recent changes made to this document New information added since added since last  last update (February 2015)  



Added new information:  information:  List of qualified AIX Versions - Notes on qualification This section has been updated and new information added regarding the definitions of all ‘qualified’, ‘unqualified’ and ‘not supported…’ labels. A new section on AIX versions that are no longer in development d evelopment has also been added at the end of this section.

SANsymphony-V 8.x is now ‘End of Life’ Please see End of Life Notifications  Notifications  http://datacore.custhelp.com/app/answers/detail/a_id/1329 http://datacore.custhelp.com/app/answers/detail/a_id/1329  

Previous changes made to this document Please see page 15 page 15

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Host Configuration Guide – IBM AIX 

 

 

List of qualified AIX Versions Notes on qualification DataCore Software will always always support  support any SANsymphony-V installation that has a valid support contract. Even installations that are using Hosts listed as ‘not supported’ will still be able to get technical support but we will never  guarantee  guarantee the behavior of a Host operating system that is listed as ‘not supported …’ if using Mirrored Virtual Disks. 

Qualified AIX versions that are listed as qualified  are considered fully ‘supported’ with redundant, mirrored Virtual Disks as long as all the configuration settings listed in this document, and that are specific to your AIX versions have been bee n followed.

Unqualified AIX versions that are listed as unqualified  have  have not been tested with SANsymphony-V and so may not work (i.e. failover or failback) as expected with redundant, mirrored Virtual Disks; even if all the configuration settings listed in this document, and that are specific to your AIX version, have been followed. Unqualified AIX versions can be ‘self -qualified’ by following the process documented here:  DataCore Component Self-Qualification Process http://datacore.custhelp.com/app/answers/detail/a_id/1506

Not Supported with Mirrored or Dual Virtual Disks These AIX versions are only supported when using non-mirrored Virtual Disks. Any Mirrored or Dual Virtual Disk served to a Host operating system indicated as ‘not supported …’ is done at the user’s own risk.   Versions that are explicitly marked as not supported  can  can never be ‘self -qualified’. 

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   AIX versions? What about other  AIX All other  AIX  AIX versions (i.e. newer) that are not  listed  listed in this document are considered as unqualified  for  for mirrored or dual dual Virtual Disks Disks when  when using SANsymphony-V and, just like all the unqualified versions of AIX that are are listed  listed in this document, the behavior with SANsymphony-V cannot be guaranteed.

These other distributions can also ‘self -qualified’ by following the same process mentioned in the previous page. Non-mirrored Virtual Disks are always supported, even on ‘other’ distributions. 

AIX versions that are no longer in development Support for any AIX versions that is considered ‘End of Life’ by the vendor or has no active development/Long Term Support can still be self-qualified but only if there is an agreed ‘support contract’ with the supplier/HP.  In this case, DataCore Technical Support will help the customer to get the Host Operating system accessing Virtual Disks, but will not then do any root-cause root-cause analysis.  analysis.

AIX The following table shows which specific versions of each version of AIX A IX that are considered Qualified (     )   , Unqualified (?) or (?) or Not Supported with Mirrored or Dual Virtual  ), Disks (  X  ) with SANsymphony-V  1  Note: iSCSI connections to AIX Hosts are not supported. SANsymphony-V Version 9.x

Version 10.x

 AIX

ALUA

Non-ALUA

ALUA

Non-ALUA

5.2









5.3



?





6.1



 

 

?

7.1





 

 

1 See

the section  section Notes on qualification  qualification on page 4 for definitions of Qualified , Unqualified  and  and Not Supported with Mirrored or Dual Virtual Disks  Disks  

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DataCore Server Settings These are the Host-specific settings that need to be configured directly on the DataCore Server. See the Registering Hosts section from the SANsymphony-V Help: http://www.datacore.com/SSV-Webhelp/Hosts.htm  http://www.datacore.com/SSV-Webhelp/Hosts.htm 

Operating System Type

AIX 5.2 When registering the Host running AIX versions 5.2 with ML9 or earlier , choose the ‘IBM  AIX Native MPIO Legacy’  entry. When registering the Host running AIX versions 5.2 with TL10 or greater , choose the ‘IBM  AIX’ entry.

AIX 5.3 When registering the Host running AIX versions 5.3 with ML5 or earlier , choose the ‘IBM  AIX Native MPIO Legacy’  entry. When registering the Host running AIX versions 5.3 with TL6 or greater , choose the ‘IBM    AIX’ entry.

AIX 6.1 and 7.1 When registering the Host running AIX version 6.1.x , choose the ‘IBM AIX’ entry.

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  Port Roles Ports used for serving Virtual Disks to Hosts should only have the Front End (FE) role enabled. Mixing other Port Role types Role types may cause unexpected results as Ports that only  have  have the FE role enabled will be turned off when the DataCore Server software is stopped (even if the physical server remains running). This guarantees that any Hosts do not still try to access FE Ports, for any reason, once the software is stopped.  Any   Port Port with the Mirror and/or Back End role enabled do not  shut  shut off when the DataCore Server software is stopped, but remain active.

Mirrored or Dual Virtual Disks When registering the Host, Multipathing Support  should  should be enabled so that Mirrored Virtual Disks or Dual Virtual Disks can be served to Hosts from all available DataCore FE ports. See the Multipathing Support section from the SANsymphony-V Help: http://www.datacore.com/SSV-Webhelp/Hosts.htm

Asymmetrical Logical Unit Access (ALUA) support ALUA is not supported for AIX Hosts.  Single Virtual Disks Single Virtual Disks (i.e. that are not mirrored or are not configured as Dual) can still be served to multiple Hosts and/or multiple Host Ports from one or more DataCore Server FE Ports if required; in this case the Host can use its own multipathing software to manage the multiple Host paths to the Single Virtual Disk as if it was a Mirrored or Dual Virtual Disk. Note: Hosts that only have Single Virtual Disks served to them do not need Multipathing Support  enabled  enabled unless they have other  Mirrored  Mirrored or Dual Virtual Disks served as well.

Serving Virtual Disks to the Hosts for the first time DataCore recommends that before before serving  serving Virtual Disks to a Host for Host for the first time to time to make sure that access to all FE paths for all DataCore Servers S ervers are correctly discovered on the Host and that from within the SANsymphony-V Management Console the Virtual Disks are marked Online Online and  and up to date and date and that the storage sources have a host access of access of Read/Write Read/Write..

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  Mappings DataCore recommend that the same Virtual Disk served to more than one Host or Host Port should use same LUN number for its mapping. While Virtual Disks have their own unique Network Address Authority (NAA) identifier, DataCore cannot guarantee that this is enough for a Host Operating System to identify the same sa me Virtual Disk served to different Paths on the same Host. Using the same LUN often guarantees some sort of consistency for device identification in these cases. Also see the SCSI Standard Inquiry Data section from the SANsymphony-V Help: http://www.datacore.com/SSV-Webhelp/Changing_V irtual_Disk_Settings.htm   http://www.datacore.com/SSV-Webhelp/Changing_Virtual_Disk_Settings.htm Note: The LUN number for Mirror Paths does not need to be the same as the Front End port mappings (or indeed as other Mirror Path mappings for the same Virtual Disk) as the Host does not see these.

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Host Settings These are the Host-specific settings that need to be configured directly on the Host Server.

Applies to any AIX Host Install the ‘DataCore ‘DataCore Support for AIX MPIO’ MPIO ’ software  software  In order for SANsymphony-V Virtual Disks to be recognized as ‘MPIO-capable’ disk devices on AIX, additional software needs to be installed on the Host. Please download and install the DataCore Support for AIX MPIO software MPIO  software from the DataCore Technical Support website (a login is required). All installation instructions can be found in the release notes that come with the software: DataCore Software Downloads http://datacore.custhelp.com/app/answers/detail/a_id/1419

Setting Disk Timeouts Once DataCore Virtual Disk(s) have been discovered on the Host, change the Disk rw_timeout  to  to 60 seconds. To determine the current rw_timeout  value,  value, run the command:

lsattr –l hdiskX –E 

Where ‘X’ is the number of the DataCore Disk Device (as seen on the AIX Host). Use the chdev  command  command to change the rw_timeout  to  to 60 (if not already set)

chdev –l hdiskX –a rw_timeout=60  Where ‘X’ is the number of the DataCore Disk Device (as seen on the AIX Host).

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  LUN   Configure a ‘dummy’ LUN AIX’s MPIO always requires a healthy LUN 0 to be able to detect and use additional LUNs served to the same port on the Host. DataCore recommend that a very small, non-mirrored   Virtual Disk be served up to the Host port as a ‘dummy’ LUN 0 from each DataCore Front End port to all AIX Host Ports that are intended to be used. Do not set this dummy LUN as a mirrored Virtual Disk to avoid unnecessary cases where the DataCore Server’s mirror partner will set the local  storage  storage source for the Virtual Disk as ‘down’ on the AIX Host, thereby preventing preventing potential access or discovery of  other  other LUNs served to the same Host port. There is no need to write any data to this LUN on the AIX Host.

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Appendix A

 

Notes on the Preferred Server & Preferred Path settings See the Preferred Servers and and Preferred  Preferred Paths sections from the SANsymphony-V Help: http://www.datacore.com/SSV-Webhelp/Port_Connections_and_Paths.htm  http://www.datacore.com/SSV-Webhelp/Port_Connections_and_Paths.htm 

Without ALUA enabled If Hosts are registered without  ALUA  ALUA support, the Preferred Server  and  and Preferred Path  Path  settings will serve no function. All DataCore Servers and their respective Front End (FE) paths are considered ‘equal’. 

It is up to the Host’s own Operating System or Failover Software to determine which DataCore Server is its preferred server.

With ALUA enabled

Note: ALUA is not supported for AIX Hosts so the following is for information only.

Setting the Preferred Server  to ‘Auto’ (or an explicit DataCore Server), determines the DataCore Server that is designated ‘Active Optimized’ for Host IO. The other DataCore Server is designated ‘Active Non-Optimized’.   If for any reason the Storage Source on the preferred DataCore Server becomes unavailable, and the Host Access for the Virtual Disk is set to Offline Offline or  or Disabled, then the other DataCore Server will be designated the ‘Active Optimized’ Optimized’ side. The Host will be notified by both DataCore Servers that there has been an ALUA state change, forcing the Host to re-check the ALUA state of both DataCore Servers and act accordingly. If the Storage Source on the preferred DataCore Server becomes unavailable but the Host Access for the Virtual Disk remains Read/Write Read/Write,, for example if only the Storage behind the DataCore Server is unavailable but the FE and MR paths are all connected or if the Host physically becomes disconnected  from  from the preferred DataCore Server (e.g. Fibre Channel or iSCSI Cable failure) then the ALUA state will not  change for the remaining, ‘Active Non optimized’ side. However, in this case, the DataCore Server will not prevent access to the Host nor will it change the way READ or WRITE IO is handled compared compared to the ‘Active Optimized’ side, side, but the Host will still register this DataCore Server’s Server’s Paths as ‘Active Non Optimized’ which may (or may not) affect how the Host behaves generally.

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  In the case where the Preferred Server  is set to ‘All’, then both both DataCore  DataCore Servers are designated ‘Active Optimized’ Optimized’ for Host IO. All IO requests from a Host will use all  Paths  Paths to all  DataCore  DataCore Servers equally, regardless of the dist ance ance that the IO has to travel to the DataCore Server. For this reason, the ‘All’ setting is not normally recommended. If a Host has to send a WRITE IO to a ‘remote’ DataCore Server (where the IO Path is significantly distant compared to the other ‘local’ DataCore Server), then the WAIT times accrued by having to send the IO not only across the SAN to the remote DataCore Server, but for the remote DataCore Server to mirror back  to  to the local DataCore Server and then for the mirror write to be acknowledged from the local DataCore Server to the remote DataCore Server and finally for the acknowledgement to be sent to the Host back across the SAN, can be significant. The benefits of being able to use all Paths to all DataCore Se Servers rvers for all Virtual Disks are not always clear cut. Testing is advised. For Preferred Path settings Path settings it is stated in the SANsymphony-V Help:  A preferred front-end front-end path settin setting g can also be set manually manually for a particular particular virtual disk. In this case, the manual setting for a virtual disk overrides the preferred path created by the  preferred server setting setting for the host. So for example, if the Preferred Server  is  is designated as DataCore Server A and A and the Preferred Paths are designated as DataCore Server B, B, then DataCore Server B will B will be the ‘Active Optimized’ Side not DataCore Server A. A. In a two-node two-node Server  Server group there is usually  nothing  nothing to be gained by making the Preferred Path setting different to the Preferred Server setting and it may also cause confusion when trying to diagnose path problems, or when redesigning your DataCore SAN with regard to Host IO Paths. Where there are three or more Servers in a Server Group, and where one or more of these DataCore Servers shares Mirror Paths between different DataCore Servers then setting the Preferred Path makes more sense. So for example, DataCore Server A has A has two mirrored Virtual Disks, one with DataCore Server B, B, and one with DataCore Server C and C and DataCore Server B also B also has a mirrored Virtual Disk with DataCore Server C then C then using just the Preferred Server  setting to designate the ‘Active Optimized’ side for the Host’s Virtual Disks becomes more complicated. In this case the Preferred Path setting Path setting can be used to override the Preferred Server  setting  setting for a much more granular level of control.

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Host Configuration Guide – IBM AIX 

 

 

Appendix B

 

Configuring Disk Pools See Creating Disk Pools and Adding Physical Disks from the SANsymphony-V Help: http://www.datacore.com/SSV-Webhelp/About_Disk_Pools.htm   http://www.datacore.com/SSV-Webhelp/About_Disk_Pools.htm The smaller the SAU size, the larger the number of indexes indexes are  are required, by the Disk Pool driver, to keep track of the equivalent amount a mount of allocated storage compared to a Disk Pool with a larger SAU size; e.g. there are potentially four times as many indexes required in a Disk Pool using a 32MB SAU size compared to one using 128MB – the default SAU size. As SAUs are allocated for allocated for the very first time time, the Disk Pool needs to update these indexes and this may  cause  cause a slight delay for IO completion and might  be  be noticeable on the Host. However this will depend on a number of factors such as the speed of the physical disks, the number of Hosts accessing the Disk Pool and a nd their IO READ/WRITE patterns, the number of Virtual Disks in the Disk Pool and their corresponding Storage Profiles. Therefore, DataCore usually recommend using the default SAU size s ize (128MB) as it is a good compromise between physical storage allocation and IO overhead during the initial SAU allocation index update. Should a smaller SAU size b be e preferred, the configuration configuration should be tested to make sure that a potential increased number of initial SAU allocations does not impact the overall Host performance.

Reclaiming Storage from Disk Pools Using SCSI UNMAP / ATA Trim commands As of SANsymphony-V 9.0 PSP4 there is support for ATA Trim commands; however please refer to your vendor’s documentation to determine which version of AIX including which file system type(s) support Trim commands. The SCSI UNMAP feature is not  supported  supported with AIX Hosts on DataCore Servers.

Automatic Reclamation Since SANsymphony-V 9.0 PSP4 the PSP4 the DataCore Server will, in the background, continuously scan each Physical Disk in a Pool for any SAUs that contain all-zero all-zero data  data which are then reclaimed back into the Disk Pool. The Automatic The Automatic Reclamation Reclamation process  process runs at a low priority, so as to not potentially interfere with overall Disk Pool performance, and so will generally take longer to scan a Physical Disk in a Pool compared to a Manual Reclamation  Reclamation  request (see below). However no user intervention is required. required.

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  Manual Reclamation For AIX Hosts that either do not support the fstrim the fstrim command,  command, or are using Virtual Disks served from DataCore Servers running SANsymphony-V 9.0 PSP3 update2 or earlier (including all versions of SANsymphony-V 8.x ); ); a suggestion would be to create a sparse file  file  of an appropriate size (If there is enough free space available in the file system) and then zero-fill it using the dd  command.  command. This example will write zeroes within an ‘empty’ file of 2GB in size (called ‘my_file’ ) using the dd command:

dd if=/dev/zero of=my_file bs=1024 count=2097152

Then either wait for an Automatic an Automatic Reclamation Reclamation to  to take place or run a Manual Reclamation. Reclamation.

See the Performing Reclamation section from the SANsymphony-V Help: http://www.datacore.com/SSV-Webhelp/Reclaiming_Virtual_Disk_Space.htm Note that it is also possible to script manual reclamation using the Start-DcsVirtualDiskReclamation PowerShell Start-DcsVirtualDiskReclamation  PowerShell Command.

How much storage will be reclaimed? It is impossible to predict exactly how many Storage Allocation Units (SAUs) will be reclaimed. For reclamation of an SAU to take place, it must contain only  ‘all-zero’ block data over the entire entire SAU  SAU else it will remain allocated and this is entirely dependent on how and where the Host has written its data on the DataCore LUN. For example, if the Host has written the data in such a way that every allocated SAU contains a small amount of nonzero block data, even if the total t otal amount of data is significantly less than tthe he total amount of SAU allocation, then no SAUs can be reclaimed.

It may be possible, in some cases, to use the Host Operating System’s own defragmentation defragmentation   tools to force the non-zero block data to be moved to a more contiguous pattern, so leaving the ‘end’ of the DataCore LUN full of SAUs that no longer have non-zero data on them that can then be reclaimed. However care should be taken that the act of defragmenting the data does not itself cause more SAU allocation as the block data is moved around during the reorganization. DataCore Software can offer no guarantees.

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Previous Changes 2015 February 2015 

 

Updated section:  section:  List of qualified AIX Versions AIX 7.1 is now qualified with SANsymphony-V 10.x using non-ALUA non-ALUA settings.  settings. Note: iSCSI is still not considered qualified at this time; all qualified versions are with Fibre Channel only.

2014 December 2014 No new technical information has been added but this t his document now combines all of DataCore’s AIX-related information from older Technical Bulletins into a single document including:

Technical Bulletin 6: “  AIX Hosts”  Hosts”   Technical Bulletin 8: “Formatting Host’s File Systems on Virtual Disks created from Disk Pools”   Pools”   Technical Bulletin 11: “Disk Timeout Settings on Hosts”   Technical Bulletin 16: “ Reclaiming Space in Disk Pools”  

 



Added new information:  information:  Which Distributions are qualified? Added new tables to show which versions are explicitly qualified , unqualified  and  and not supported with either SANsymphony-V 8.1 PSP1 Update 4, 9.x and 10.x, and if the configuration is with with or  or without  ALUA enabled  ALUA  enabled Hosts. Note that the minimum requirement for SANsymphony-V 8.x is now 8.1 PSP1 Update 4

 Appendix A This section gives more detail on the Preferred Server  and  and Preferred Path settings Path settings with regard to how it may affect a Host.  Appendix B This section incorporates information regarding “Reclaiming Space in Disk Pools” (from Technical Bulletin 16) that is specific to AIX Hosts.  Hosts.  

 



Updated existing entries:  entries:  Host Settings - Improved explanations to most of the required Host Settings and Settings and DataCore Server Settings generally. Settings  generally.

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  2013 Technical Bulletin 6: “  AIX Hosts”  Hosts”    April 2013 Removed all references to SANmelody as this is now ‘End of Life’ of December 31 2012. Removed all references to iSCSI as this is not supported with AIX. July 2012 Updated for SANsymphony-V 9.x. No new technical information. January 2012 Updated DataCore Server and Host minimum requirements. Removed all references to ‘End of Life’ SANsymphony and SANmelody versions that are no longer supported as of December 31 2011. June 2011 Added AIX 7.1. November 2011 Removed all references to ‘End of Life’ SANsymphony and SANmelody versions that are no longer supported as of July 31 2011. October 2011 Added SANsymphony-V 8.x July 2009 Added AIX 6.1.x. March 2009 Initial publication of Technical Bulletin. Added AIX 5.2 TL10  

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COPYRIGHT Copyright © 2015 by DataCore Software Corporation. All rights reserved. DataCore, the DataCore logo and SANsymphony are trademarks of DataCore Software Corporation. Other DataCore product or service names or logos referenced herein are trademarks of DataCore Software Corporation. All other products, services and company names mentioned herein may be trademarks of their respective owners. ALTHOUGH THE MATERIAL PRESENTED IN THIS DOCUMENT IS BELIEVED TO BE ACCURATE, IT IS PROVIDED “AS IS” AND USERS MUST TAKE ALL RESPONSIBILITY FOR

THE USE OR APPLICATION OF THE PRODUCTS DESCRIBED AND THE INFORMATION CONTAINED IN THIS DOCUMENT. NEITHER DATACORE NOR ITS SUPPLIERS MAKE ANY EXPRESS OR IMPLIED REPRESENTATION, WARRANTY OR ENDORSEMENT REGARDING, AND SHALL HAVE NO LIABILITY FOR, THE USE OR APPLICATION OF ANY DATACORE OR THIRD PARTY PRODUCTS OR THE OTHER INFORMATION REFERRED TO IN THIS DOCUMENT. ALL SUCH WARRANTIES (INCLUDING ANY IMPLIED WARRANTIES OF MERCHANTABILITY, NON-INFRINGEMENT, FITNESS FOR A PARTICULAR PURPOSE AND AGAINST HIDDEN DEFECTS) AND LIABILITY ARE HEREBY DISCLAIMED TO THE FULLEST EXTENT PERMITTED BY LAW. No part of this document may be copied, reproduced, translated or reduced to any electronic medium or machine-readable form without the prior written consent of DataCore Software Corporation

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