HPUX Configuration Guide (Formerly Known as FAQ 1592)
Known Issues in HPUX Configuration Guide
Overview
This guide provides configuration settings and considerations for Hosts running HPUX with SANsymphony.
Basic HPUX storage administration skills are assumed including how to connect to iSCSI and Fibre Channel target ports and the discovering, mounting, and formatting of disk devices.
Change Summary
Refer to DataCore FAQ 838 For the latest version of the FAQ and see the Previous Changes section that lists the earlier changes made to this document.
Changes since January 2019
| Section(s) | Content Changes |
|---|---|
| General Updates |
This document has been reviewed for SANsymphony 10.0 PSP11. No additional settings or configurations are required. |
HPUX Compatibility List
HPUX Operating System Versions
Applies to all versions of SANsymphony 10.x.
| HPUX | WITH AULA | WITHOUT AULA |
|---|---|---|
| 11.23 or earlier | Not Supported | Not Supported |
| 11.31 | Not Qualified | Qualified |
- Qualified vs Not Qualified vs Not Supported
- Refer to Qualified vs Not Qualified vs Not Supported for definitions.
- DataCore Server Port connections
- For HPUX hosts, only Fibre Channel Front-end (FE) connections are supported.
- FE iSCSI connections are not supported.
- SCSI UNMAP
- There is no support for SCSI UNMAP from HPUX hosts.
Qualified vs Not Qualified vs Not Supported
Qualified
This combination has been tested by DataCore and all the host-specific settings listed in this document applied using non-mirrored, mirrored and dual virtual disks (vDisks).
Not Qualified
This combination has not yet been tested by DataCore using Mirrored or Dual vDisks types. DataCore cannot guarantee 'high availability' (failover/failback, continued access, etc.) even if the host-specific settings listed in this document are applied. Self-qualification may be possible. See DataCore Technical Support FAQ #1506.
Mirrored or dual vDisks types are configured at the user's risk; however, any problems that are encountered while using HPUX versions that are 'Not Qualified' will still get root-cause analysis.
Non-mirrored vDisks are always considered 'Qualified' - even for 'Not Qualified' combinations of HPUX/SANsymphony.
Not Supported
This combination has either failed 'high availability' testing by DataCore using mirrored or dual vDisks types; or the operating System's requirements/limitations (e.g. age, specific hardware requirements) make it impractical to test. DataCore will not guarantee 'high availability' (failover/failback, continued access, etc.) if the host-specific settings listed in this document are applied. Mirrored or dual vDisks types are configured at the user's risk. Self-qualification is not possible.
Mirrored or dual vDisks types are configured at the user's risk; however, any problems that are encountered while using HPUX versions that are 'Not Supported' will get best-effort DataCore Technical Support (e.g. to get access to vDisks) but no root-cause analysis will be done.
Non-mirrored vDisks are always considered 'Qualified' - even for 'Not Supported' combinations of HPUX/SANsymphony.
HPUX versions that are End of Support Life
Self-qualification may be possible for versions that are considered ‘Not Qualified’ by DataCore but only if there is an agreed ‘support contract’ with HP. Contact DataCore Technical Support before attempting any self-qualification of HPUX versions that are End of Support Life (EOSL).
For any problems that are encountered while using HPUX versions that are EOSL with DataCore Software, only best-effort DataCore Technical Support will be performed (e.g. to get access to vDisks). Root-cause analysis will not be done.
Non-mirrored vDisks are always considered 'Qualified'.
DataCore Server Settings
Operating System Type
When registering the Host running HP-UX choose the ‘HP HP-UX’ menu option.
Port Roles
Ports that are used to serve virtual disks (vDisks) to hosts should only have the Front-end (FE) role checked. While it is technically possible to check additional roles on an FE port (i.e., Mirror and Backend), this may cause unexpected results after stopping the SANsymphony software.
Any port with FE role (and is serving vDisks to hosts) also has either the mirror and/or backend role enabled will remain ‘active’ even when the SANsymphony software is stopped. There is some slight difference in behavior depending on the version of SANsymphony installed.
SANsymphony 10.0 PSP7 and earlier
Any port that has the mirror and/or back-end role checked will remain ‘active’ after the SANsymphony software has been stopped.
SANsymphony 10.0 PSP8 and later
Only ports with the back-end role checked will remain ‘active’ after the SANsymphony software has been stopped.
FE ports that are serving vDisks but remain active after the SANsymphony software has been stopped can cause unexpected results for some host operating systems as they continue to try to access vDisks from the ‘active’ port on the now-stopped DataCore Server. This, in turn, may end up delaying host fail-over or result in complete loss of access from the host’s application/virtual machines (VM).
Multipathing
The Multipathing Support option should be enabled so that mirrored vDisks or dual vDisks can be served to hosts from all available DataCore FE ports. Refer to Multipathing Support for more information.
Non-mirrored vDisks and multipathing
Non-mirrored vDisks 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 vDisk as if it was a mirrored or dual vDisk.
ALUA Support
ALUA (Asymmetrical Logical Unit Access) is not supported.
Serving Virtual Disks
The first time
DataCore recommends that before serving vDisks for the first time to a host, all DataCore FE ports on all DataCore Servers are correctly discovered by the host first.
Then, from within the SANsymphony Console, the vDisk is marked Online, up to date and that the storage sources have a host access status of Read/Write.
To more than one host port
DataCore vDisks always have their own unique Network Address Authority (NAA) identifier that a Host can use to manage the same vDisk being served to multiple ports on the same host server and the same vDisk being served to multiple Hosts.
While DataCore cannot guarantee that a disk device's NAA is used by a host's operating system to identify a disk device served to it over different paths generally we have found that it is. Additionally, while there is sometimes a convention that all paths by the same disk device always using the same LUN 'number' guarantees consistency for device identification, this may not be technically true. Always refer to the Host Operating System vendor’s documentation for advice on this.
DataCore's Software does, however always try to create mappings between the host's ports and the DataCore Server's FE ports for a vDisk using the same LUN number where it can. The software will first find the next available (lowest) LUN 'number' for the Host- DataCore FE mapping combination being applied and will then try to apply that same LUN number for all other mappings that are being attempted when the vDisk is being served. If any Host-DataCore FE port combination being requested at that moment is already using that same LUN number (e.g. if a host has other vDisks served to it from previous) then the software will find the next available LUN number and apply that to those specific Host-DataCore FE mappings only.
HPUX Host Settings
Physical Volume Timeout
Set the timeout value to 60 seconds using the following commands:
Known Issues in HPUX Configuration Guide
The following is intended to make DataCore Software users aware of any issues that affect performance, access or may give unexpected results under particular conditions when SANsymphony is used in configurations with HPUX Hosts.
These known issues may have been found during DataCore’s own testing but others may have been reported by our users when a solution was found that was not to do with DataCore’s own products.
DataCore cannot be held responsible for incorrect information regarding another vendor’s products and no assumptions should be made that DataCore has any communication with these other vendors regarding the issues listed here.
We always recommend that the vendor’s should be contacted directly for more information on anything listed in this section.
For ‘Known issues’ that apply to DataCore Software’s own products, please refer to the relevant DataCore Software Component’s release notes.
Multiple roles assigned to SANsymphony ports serving virtual disks to the host can lead to misleading statuses on HP-UX
If a SANsymphony Server port used for serving virtual disks (vDisks) to the HP-UX host, has either the Back-end (BE) or Mirror (MR) roles set - in addition to Front-end (FE) role - then the HP- UX host may show discovered LUNs with a status of 'NO-HW' (no hardware) after any subsequent path failures.
This is cosmetic and has no functional impact. Remove any BE or MR roles from all ports used to serve vDisks to HP-UX Hosts.
Appendices
A: Preferred Server and Preferred Path Settings
Without ALUA Enabled
If hosts are registered without ALUA support, the Preferred Server and Preferred 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 Operating System or Failover Software to determine which DataCore Server is its preferred server.
With ALUA Enabled
ALUA is not supported for HPUX Hosts.
Refer to the Preferred Servers and Preferred Paths sections in Port Connections and Paths for more information.
B: Reclaiming Storage from Disk Pools
How Much Storage will be Reclaimed?
This is impossible to predict.
SANsymphony can only reclaim Storage Allocation Units (SAU) that have no block-level data on them. If a host writes its data ‘all over’ its own filesystem, rather than contiguously, the amount of storage that can be reclaimed may be significantly less than expected.
Defragmenting Data on Virtual Disks
It may be possible to use a host’s defragmentation tools to consolidate data spread out all over the host’s filesystem but care should be taken as even more storage may be allocated while the existing data is defragmented.
Once any defragmentation is completed then additional steps will need to wipe the ‘free’ filesystem space on the host and then use SANsymphony’s ‘Manual Reclamation’ feature.
Notes on SANsymphony's Reclamation Feature
Automatic Reclamation
SANsymphony checks for any ‘zero’ write I/O as it is received by the disk pool and keeps track of which block addresses they were sent to. When all the blocks of an allocated SAU have received ‘zero’ write I/O, the storage used by the SAU is then reclaimed.
Mirrored and replicated virtual disks (vDisks) will mirror/replicate the ‘zero’ write I/O so that storage can be reclaimed on the mirror/replication destination DataCore Server in the same way.
Manual Reclamation
SANsymphony checks for ‘zero’ block data by sending read I/O to the storage. When all the blocks of an allocated SAU are detected as having ‘zero’ data on them, the storage used by the SAU is then reclaimed.
Mirrored vDisks will receive the manual reclamation ‘request’ on all DataCore Servers involved in the mirror configuration at the same time and each DataCore Server will read from its own storage.
The Manual reclamation ‘request’ is not sent to replication destination DataCore Servers from the source. Replication destinations will need to be manually reclaimed separately.
Reclaiming Storage on the Host Manually
A suggestion would be to create a ‘sparse file’ of an appropriate size and write zeroes it using the ‘dd’ command.
Here is an example with a 2TB sparse file:
Previous Changes
| Section(s) | Content Changes | Date |
|---|---|---|
| General Updates | This document has been reviewed for SANsymphony 10.0 PSP8. No additional settings or configurations are required. | October 2019 |
| The DataCore Server Settings – Port Roles |
Updated the content. |
July 2019 |
| General Updates |
Removed the following: All information regarding SANsymphony-V 9.x as this version is end of life (EOL). Refer to End of life notifications for DataCore Software products for more information. |
|
| General Updates | This document has been reviewed for SANsymphony 10.0 PSP8. No additional settings or configurations are required. | October 2018 |
| HPUX Compatibility List |
Updated the following: Version 11.31 with SANsymphony 10.x using ALUA has been changed from ‘Not Supported’ to ‘Not Qualified’ thereby allowing self-qualification. |
November 2017 |
| This document has been reviewed for SANsymphony 10.0 PSP7. No updates were required. | ||
| General Updates |
Updated the following: This document has been reviewed for SANsymphony 10.0 PSP7. No additional settings or configurations are required |
February 2018 |
|
Removed the following: Appendix B – Configuring Disk Pools The information here has been removed as it is now superseded by the information in: The DataCore Server - Best Practice Guidelines. What was previously 'Appendix C' has now been moved to 'Appendix B'. |
||
| General Updates |
This document has been reviewed for SANsymphony 10.0 PSP6. No updates were required. |
May 2017 |
| Appendix C - Reclaiming storage |
Updated the following: Automatic and Manual reclamation These two sections have been re-written with more detailed explanations and technical notes. |
November 2016 |
| General Updates |
Updated the following: This document has been reviewed for SANsymphony 10.0 PSP5. No updates were required. |
July 2016 |
| Known Issues |
Added the following: Multiple roles assigned to SANsymphony-V ports serving Virtual Disks to the Host can lead to misleading statuses on HP-UX. This was originally documented as http://datacore.custhelp.com/app/answers/detail/a_id/1052. |
October 2015 |
| List of qualified HP-UX Versions - Notes on qualification |
Added the following: This section has been updated and new information added regarding the definitions of all ‘qualified’, ‘unqualified’ and ‘not supported…’ labels. A new section on HP-UX versions that are no longer in development has also been added at the end of this section. |
June 2015 |
| General Updates |
Updated the following: This document now combines all of DataCore’s HP-UX-related information from older Technical Bulletins into a single document including: Technical Bulletin 8: “Formatting Host’s File Systems on Virtual Disks created from Disk Pools” Technical Bulletin 11: “Disk Timeout Settings on Hosts” Technical Bulletin 16: “Reclaiming Space in Disk Pools” |
February 2015 |
|
Added the following: List of qualified HP-UX Versions Added new tables to show which versions are explicitly qualified, unqualified and not supported with either SANsymphony-V 9.x or 10.x, and if the configuration is with or without ALUA enabled Hosts. Note that SANsymphony-V 8.x is now considered ‘End of Life’. Appendix A This section gives more detail on the Preferred Server and Preferred 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 HP-UX Hosts. |