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Incoherent capacity information with XP10000?

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Dario_C
Regular Contributor.

Incoherent capacity information with XP10000?

Hello,

In our infrastructure we use Storage Essentials 6.2.0.119 and an XP10000 Storage System.

The problem is that SE Capacity Manager shows different values from the XP CommandView Console.

SE Capacity Manages says that the total raw capacity is 10.419.906,60 MB, while the XP CommandView Console says that the real total capacity is 12.929GB.

Attached there are the screenshots that shows these values.

Some other important information I can give is that after the SE installation we have upgraded the XP with more disks.

What could be happened?

 

Thanks in advance,

Dario

4 REPLIES
WileyThrasher
Super Contributor.

Re: Incoherent capacity information with XP10000?

Note: It would be suggested to view the Array Centric HP XP report and report definition provided in SE Reporter:

 

SE Reporter > Report Pack > Standard Reports > Storage > Array Centric Report - HP XP

 

From the SE Reporter (aka Report Optimizer) Array Centric Report - HP XP Array Report Definition Tab:

 

XP Array Report Definition


Array Specific Reporting

The purpose of these array specific reports is to aid customers in the validation of Storage
Essentials data and to explain the terminology differences between Storage Essentials and
vendor/array specific tools. 

There are a number of issues to address:

1.  While SE is built on standards and uses standards based terminology most vendor tools are not.
2.  All vendors compute total/used/available type capacity differently.
3.  Most vendors use terms and definitions associated with their arrays and many times even very between array model types.
4.  Some vendors use a 1000 byte KByte instead of a 1024 byte KByte.  We even have seen vendors mix this usage in a single tool.
5.  No matter which tool is used there is a certain amount of rounding performed by the tools and many times some truncating, on some arrays this can add up to a 1% or 2% difference in numbers when comparing tools.
6.  Most capacities in the arrays either using our tool or vendor specific tools are summaries of components - depending on which components are summed can vary the results.
7.  Configuration practices at individual customers can impact reports.  Many customers have a method to 'reserve' space on large arrays for future projects.  Depending how this is performed Storage Essentials may or may not see this as 'used' capacity.

 

Report Definition - To define HP XP and Storage Essentials terms and show the relationship between these terms.  To demonstrate the use of Report Optimizer to calculate capacities that can be verified with Remote Web Console.


HP XP Terminology-


Total  Capacity:  On XP 12000 series and older arrays this value is the total allocated ldev plus total unallocated ldev  plus reserved capacity and does not include free space (unformatted capacity).  On XP 24000 and newer this value is the total allocated ldev plus total unallocated ldev plus reserve plus free space. 


Allocated LDEV Capacity:   Post Raid capacity that is formatted into LDEVs and assigned to a host security group (HSG).  This does not include LDEV capacity from Thin Provisioning or Snapshot Pools, this space is accounted for in the ‘Reserved Capacity’ calculation. This does include CA Journal capacity.


Unallocated LDEV Capacity:   Post Raid capacity that is formatted into LDEVs and not assigned to a host security group (HSG).  In XP24000 and newer arrays this does not include LDEV capacity from Thin Provisioning Pools or Snapshot Pools, this space is accounted for in the ‘Reserved Capacity’ calculation.  In older arrays the space for snapshot and journal pools is included in Unallocated LDEV Capacity.
 
Free Space:  Capacity that is part of a Raid Group in the array but not formatted into LDEV capacity. 


Reserved Capacity:  On 24K and newer arrays it is the Total capacity of LDEVs assigned to the Thin Provisioning pools ,Snapshot pools, Journal pools, System Disks for Volume Shredder, Auto LUN Reserved volumes, and Quorum disks for external storage.  On older arrays it is only the Auto LUN reserved space.
 


Storage Essentials Terminology -

Total Capacity:  Sum of all post raid capacity in the array that is part of a Raid Group.  This does include ‘free space’ and ‘reserved’ capacity.


Mapped Capacity:  Capacity of storage volumes assigned to a Host Security Group (HSG) and have a WWN assigned to that HSG.


Unmapped Capacity:  Capacity of storage volumes that are not assigned to a Host Security Group (HSG).  This also includes storage volumes that may be assigned an HSG but the HSG does not have a WWN configured.

 


Which Storage Essentials capacity numbers relate to Remote Web Console (RWC) output in this report:


Total Capacity – RWC Total Capacity including ‘Free Space’.  This is a calculated value in RWC by adding Reserved, Unallocated, Allocated, etc.  RWC also rounds and truncates values which can cause the RWC Total Capacity value to vary by 1-2GB by simply allocating storage to hosts.  The SE values do not round and truncate before the summarizations so tend to not vary by simply allocating space to a host.


Mapped Capacity – RWC Allocated LDEV capacity minus the LDEVs assigned to a Host Security Group (HSG) without a WWN assigned.  This report resolves this by simply summing the LDEVs assigned to an HSG but not looking for a WWN.  Also missing is the CA Journal capacity which shows as Allocated LDEVs in RWC.  This report resolves this by adding the Total Capacity of the Journal pools in the Allocated LDEV capacity variable.


Unmapped Capacity – RWC Unallocated LDEV capacity.


Pool Total Capacity – RWC Reserved Capacity on 24k and newer arrays is the sum of the full LDEV capacity of the Thin Provisioning Pool, Journal Group Pools, and the Snapshot Pool plus the sum of the System Shredder volumes, Quorum volumes, and Auto LUN reserved volumes.  The SE equivalent of Reserved Capacity is the sum of the ‘Total Capacity’ of the THP, Journal Groups, and Snapshot Pools.  RWC Free Space is the amount of space in a Raid Group that has not been formatted into an LDEV.  This is the SE equivalent of the sum of the ‘Free Space’ Pools ‘Total Capacity’.

Current known limitations – Currently there is a corner case where SE does not map a storage volume to a port.  If Security is enabled on a port, host security groups (HSG) are created, and storage volumes are assigned to the HSG then the security for the port is disabled SE no longer recognizes the HSG so the volumes no longer show a relationship to the port or HSG.  These volumes show as Uallocated LDEV Capacity in this report currently. 

Wiley Thrasher
Storage Management Expert
HP Storage TCE and Quality Tiger Team
WW L3 Pre-sales Support
Hewlett-Packard Company
WileyThrasher
Super Contributor.
Solution

Re: Incoherent capacity information with XP10000?

Also note that array capacity, and array configuration changes (such as having added physical disks) are collected during the SE Setup Step 3 "Details" collection phase (aka "Get Details" aka "GAED") only.

In some cases, folks forget the step to define a nightly schedule for GAED of their entire environment, and/or, forget to add systems to the schedule after a subsequent device discovery as is required, and therefore have stale configuration details in the database, and no recent capacity measurements for their arrays - only the last manually initiated  "Get Details" during the initial service implementation.

 

Assure that Configuration > Discovery > Discovery Schedule has been configured and is running, usually once a day in the late evening or early morning hours against all systems.

Wiley Thrasher
Storage Management Expert
HP Storage TCE and Quality Tiger Team
WW L3 Pre-sales Support
Hewlett-Packard Company
Dario_C
Regular Contributor.

Re: Incoherent capacity information with XP10000?

Hello,

Thanks for your replies.

 

Problem was due to the CVAE Device Manager we use to discover the XP, having stale and old data.

But your information were also very useful, because now I'm able to understand better the SE Capacity information and I've scheduled the GAED every night, forcing also the refresh of the Device Manager.

 

Sorry, but we started using this product recently....

 

I will consider the problem solved and close this thread.

 

Thanks again,

Dario 

WileyThrasher
Super Contributor.

Re: Incoherent capacity information with XP10000?

HI Dario,

 

Indeed, you encountered a known but sometimes non-obvious case regarding data collection - in the case of using external proxy based discovery (XP arrays via command view advanced edition) compared to our direct discovery method via the svp console - the data gathered via the proxy is only as up to date as it's last sync to the array, which may be hours or potentially days old (when last refreshd in the GUI itself). By selecting the option of "force device manager refresh" in SE's Setup Step 3 "Details" data collection SE will trigger this refresh automatically prior to our gathering of data. I mention SE's unique direct discovery method as it's preferred for HP XP arrays not only for the reason of avoiding stale configuration data, but also as it provides a faster data collection and SE also gains visibility of the back-end of the array allowing for SE to map External Storage relationships (if applicable) and combined with SE's Performance Pack Enterprise plug-in.

 

Note: The force device manager refresh is also applicable to HDS arrays (which require a HDvM proxy - lacking option of direct discovery), and EMC Symm arrays via Solutions Enabler proxy host.

 

Thank you for taking the time to respond to the thread with the resolution to your issue.

 

Sincerely,

 

Wiley

Wiley Thrasher
Storage Management Expert
HP Storage TCE and Quality Tiger Team
WW L3 Pre-sales Support
Hewlett-Packard Company