What are the recommended system read/write cache values for VNX arrays?

Issue:
VNX Block-only arrays ship by design with zero read and write cache values.
VNX Unified/File system installations set read and write cache values contrary to "best practices"

Cause:

This article offers basic guidance for suggested cache settings on VNX Block systems at installation time. VNX Block-only systems ship from the factory without any Read/Write cache values assigned, and with cache totally disabled on both storage processor (SPs). The Block-only versions of the VNX Installation Guides instructs users to setup the initial Read/Write cache settings for the array during the installation process. In addition, users should understand that the initial cache settings may need to be changed once normal and proper system operation/performance has been determined.

For VNX File/Unified systems, the installation of the File component [as a File re-install or as a Block-to-Unified upgrade], at File OE versions 7.0.12.0/7.0.13.0/7.0.14.0, sets the Read cache values on the SPs to a flat value of 512 MB/SP on all Unified models. However, this behavior contradicts theen standard Best Practice values for VNX arrays. Users need to be aware that they may need to manually set the Read cache value back to the desired settings after a File install.
With VNX File OE version 7.0.35.3 and later, the Block-to-Unified upgrade, or a File re-install, will not change any array cache values, if already set. However, where array cache values have not already been set, a File system installation will appropriately set the array cache values to the recommended settings outlined in the Table below. Basically, Read cache values will be set at 10% of available cache (with a Read minimum of 256 MB, and a Read maximum of 1024 MB), and the
remainder of cache assigned to Write cache as described in the table below.

Resolution:

The following recommended default cache settings (by model) should be considered as a starting point, and are valid for a Block-only or Unified installation.
Refer to the VNX Best Practices Guide for guidance on how to adjust these settings for your particular workload. Refer to knowledge base 78781 for examples
of how to change Read and Write cache values using Unisphere. 

Per Storage 

Processor Memory                        VNX5100  VNX5300  VNX5500  VNX5700  VNX7500

Max. Cache/SP (GB)                          4               8                 12              18             24/48*

Max. Write Cache (MB)

Release 32 without enablers              950           3997           6488            9706        13450/-

Max. Write Cache (MB)
Release 32 and data services**         650            2782           4738           6581         10600/16600 

 
 Allocate 10% of available cache to read (Read cache is set per SP, with a minimum of 256 MB, except for the VNX5100, and a max of 1024 MB), and the rest to write (Write cache is set per array). Please note that certain Array features, such as FAST VP and Compression, will reduce the overall memory available for Read and Write cache, hence the minimum 256 MB Read cache reference. Setting read to 10% (with min and max) would lead to the following:

• VNX5100 - Read 100 MB [Block-only system]
• VNX5300 - Read 400 MB [Block or Unified/File]
• VNX5500 - Read 700 MB [Block or Unified/File]
• VNX5700 - Read 1024 MB [Block or Unified/File]
• VNX7500 - Read 1024 MB [Block or Unified/File]  

How to gather SPcollect or Service Data Logs for EMC VNXe Series

Product: EMC VNXe Series

Resolution:

There are two ways of gathering Service Data logs collect.

1. Collecting from Unisphere GUI (Recommended Method)
2. Collecting logs through SSH

Collecting from Unisphere GUI (Recommended Method):

1. Log in to the Unisphere GUI with admin credentials.
2. Click on Settings and then on Service system.
3. Enter service password.
4. Under "System Components" highlight "Storage System".
5. Select "Collect Service Information " under "Service Actions."
6. Click "Execute service action."
7. This message is displayed: "The service data has previously been collected and is available for download. Do you want to download this existing service data or start a new process to collect new service data? Click Yes to download the existing service data file or No to start a new collection of service data."
8. Select Yes or No as appropriate to your situation.
9. Click Yes to save the files to your hard drive.

Collecting logs through SSH:

1. Open an SSH tool (like Putty).
2. Connect to VNXe management IP through Putty.
3. Log in as the service user.
4. Run the svc_dc command. It will take couple of minutes to complete.
5. Use third party scp/sftp tools like WinSCP or FileZilla to connect to VNXe management IP (log on as service).
6. Browse to /EMC/backend/service/data_collection on VNXe.
7. Copy the .tar file to your local desktop (file name looks like VNXe3100_service_data_APM00113200784_2012-01-11_21_23_26.tar).

How to gather SPcollect files or Logs for EMC VNX or Clarrion Series Array

Summary: This article describes how to gather SPcollects from a VNX Series array (including arrays with MCx), using either Unisphere, USM or Navisphere Secure CLI. Retrieving diagnostic data from a Unified array using Unisphere.

Environment: EMC Hardware: VNX Series

                       EMC Hardware: VNX Series with MCx

                       Product: VNX5100

                       Product: VNX5200

                       Product: VNX5300

                       Product: VNX5400

                       Product: VNX5500

                       Product: VNX5600

                       Product: VNX5800

                       Product: VNX5700

                       Product: VNX7500

                       Product: VNX7600

                       Product: VNX8000

                       EMC Hardware: VNX Unified/File 

                       EMC Hardware: VNX Block

                       EMC Software: VNX Operating Environment (OE) for Block 05.32

                       EMC Software: VNX Operating Environment (OE) for Block 05.33 and later

                       EMC Software: Unisphere

                       EMC Software: Unisphere Service Manager

                       EMC Software: Navisphere Secure CLI

Resolution: There are a number of methods to gather SPcollects:

1. Start and retrieve SPcollects from each SP using Unisphere.
2. Launch Unisphere Service Manager either directly or from within Unisphere. This approach has the advantage of automating the whole SPcollect gathering process and gathering File diagnostic data too.
3. Start and retrieve SPcollects from each SP using Navisphere Secure CLI.

Unisphere:

1. Launch Unisphere and login.
2. Select the VNX series array from either the dashboard or from the Systems drop-down menu. Click System on the toolbar.
3. On the right pane, under Diagnostic Files, select 'Generate Diagnostic Files - SPA'. Confirm that it is OK to continue.  "Success" will be displayed when the SPcollect starts, but this only means the script has been started and will still take several minutes to complete.
4. Repeat step 3 for SP B.
5. It will take around 15 minutes to generate a complete SPcollect file.
6. Still on the right pane, select 'Get Diagnostic files - SP A'.
7. When the SPcollect file has completed, a file with the following name will be listed: <ArraySerialnumber>_SPA_<date_time(GMT)_code>_data.zip
8. Sorting by descending order of date is a good way to find the latest SPcollect and the zip file will generally be over 10MB.  If the file has not appeared, press refresh every minute or so until the correct _data.zip file appears.
9. On the right-hand side of the box, select the location on the local computer, where the SPcollects should be transferred to.
10. On the left hand side of the box select the file to be transferred.  Note, if a file is listed that ends in runlog.txt, this indicates that the SPcollects are still running. Wait until the data.zip is created.
11. Repeat Steps 6-10 on SP B to retrieve its diagnostic files.

Unisphere Service Manager:

1. Log in to Unisphere client.
2. Select the VNX, either from the dashboard or from the Systems drop-down. Click System on the toolbar.
3. On the right pane, under Service Tasks, select 'Capture Diagnostic Data'.  This will launch USM.  Alternatively USM can be launched directly from the Windows Start menu.
4. Select the Diagnostics tab and select ‘Capture Diagnostics Data’.  This will launch the Diagnostic Data Capture Wizard.
5. The Wizard will capture and retrieve SPcollect files from both SP and Support Materials from the File storage, which will then be combined into a single zip file.

Navisphere Secure CLI:

Perform the following steps:

1. Open a command prompt on the Management Station.
2. Type cd "C:\Program Files\EMC\Navisphere CLI" - This is the default installation folder for Windows, but the path the file was installed to may have been overridden.  Other platforms, such as Linux, would have a different folder structure, but the commands are the same. The CLI folder may already be in the path statement, in which case, the commands can be run from any directory.
3. Type naviseccli -h <SP_A_IP_address> spcollect
4. Type naviseccli -h <SP_B_IP_address>spcollect
5. These commands start the SPcollect script on each SP.  Additional security information may also need to be specified
6. Wait at least 10 minutes for the SPcollects to run, before attempting to retrieve them.
7. Type naviseccli -h <SP_IP_address>managefiles -list
8. This will list the files created by SPcollect.  Check that a file with the current date and time in GMT has been created, ending with _data.zip.  If there is a file ending with .runlog instead, then the SPcollect is still running, so wait for a while longer before retrying this.
9. Type naviseccli -h <SP_IP_address>managefiles -retrieve

          This will display the files that can be moved from the SP to the Management Station.

          Example:

          Index Size in KB     Last Modified            Filename

          0     339       06/25/2013 00:45:42  admin_tlddump.txt

           ...

          10    24965     06/24/2013 23:39:53  FNM00125001234_SPB_2013-06-24_22-38- 15_32a007_data.zip

          11    41577     06/25/2013 00:17:17  FNM00125001234_SPB_2013-06-24_23-10-55_32a007_data.zip

           ...

    10.  Enter files to be retrieved with index separated by comma (1,2,3,4,5) OR by a range (1-3) OR enter 'all' to retrieve all file OR 'quit' to quit> 11

This will pull the index number 10 (the most recent ~_data.zip file) from the corresponding SP and copy it to the c:\program files\emc\navisphere cli directory, with a filename of FNM00125001234_SPB_2013-06-24_23-10-55_32a007_data.zip

Notes: While an SPcollect is running, a file ending runlog.txt will be visible.  This just tracks the progress of the SPcollect and will disappear once the SPcollect completes (it gets moved into the SPcollect data.zip file). There is no need to upload the runlog.txt by itself and it will be necessary to wait until the SPcollect completes on each SP, before uploading the data.zip files.