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Storage & Clustering Community Blog

Showing posts tagged with Dynamic Multi-Pathing and Dynamic Multi-Pathing for VMware
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A note to VOS users (now called SORT)
jmartin | 23 Feb 2011 | 1 comment

Late last year, we changed the name of Veritas Operations Services (VOS) to Symantec Operations Readiness Tools (SORT) [http://sort.symantec.com]  and we enhanced the site to help new users understand more about the available features. 

As you’ve likely seen, the main SORT webpage is geared toward educating new users about SORT features and functions. 

For previous VOS users, we suggest going directly to the MySORT page (http://mysort.symantec.com).  MySORT is the old VOS home page with a few minor changes.  You’ll see a color template difference but the old VOS functionality is still there including enhancements based on previously received feedback.

If you just want to use the tools and services, go to the MySORT page and get started (http://mysort.symantec.com).  You can generate reports for...

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New Platform (PR1) released: Veritas Storage Foundation and High Availability Solutions 5.1 SP1 PR1 for IBM AIX 7.1
Big_Bear | 23 Feb 2011 | 1 comment

 

The Symantec Global Enterprise Support and Supportability Teams are pleased to announce their acceptance of the following Platform Release (PR1) for Veritas Storage Foundation and High Availability Solutions 5.1 SP1 for IBM AIX 7.1.  

Product: Veritas SFHA Solutions 5.1 SP1 PR1 for IBM AIX 7.1

 

Download

https://fileconnect.symantec.com/LangSelection.jsp

Product guides for SFHA Solutions 5.1 SP1 PR1

https://sort.symantec.com/documents

 

Symantec Operations Readiness Tools (SORT)

 

SORT Portal:  https://sort.symantec.com/land

SORT Patches:  https://...

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New Release: Veritas Dynamic Multi-Pathing 5.1 for Windows
John H. Kelly | 02 Nov 2010 | 0 comments

Veritas Dynamic Multi-Pathing for Windows (DMPW) adds additional fault tolerance to disk storage by making use of multiple paths between a server/host computer and a disk in a storage array. A path is a connection between the server/host computer and the storage array’s disks and consists of a host adapter and a SCSI bus connection to one or more SCSI disks or a fiber optic channel connected to a hub, switch, or array. Thus, multiple paths are made possible by connecting two or more host bus adapters with either SCSI or fiber optic cabling to the storage array. DMPW manages the multiple paths so that the data on each of the array’s disks is accessible to the host computer. If a path to a disk fails, Dynamic Multi-Pathing automatically transmits data to and from the disk over an alternate path.

The paths on an array are set up to work in two ways—either in Active/Active mode, which provides load balancing of the data between multiple paths, or in Active/...

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What's being written about Veritas Dynamic Multi-Pathing
bgoodyear | 10 Dec 2010 | 0 comments

Blogger Jerome Wendt recently posted an entry about Veritas Dynamic Multi-Pathing (DMP) on his site.  You can read what he has to say about DMP and the fact that it is now available as a standalone product.  Check out his entry at:

http://symantec.dciginc.com/2010/08/symantecs-dmp-no-strings-attached.html

Now DMP is available as a standalone product to support file systems other than VxFS.  It is available now on Solaris, AIX, and Linux.  Coming in November, DMP as a standalone product will be available on HP-UX and Windows.  DMP is still included with Storage Foundation and will be in the future.  The advantage with DMP as a separate product is that now DMP can be added to an existing server without having to convert any file systems to VxFS. 
 

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Configuring online array support using Array Policy Module (APM)
Ameya | 10 Dec 2010 | 1 comment
Array Policy Module (APM)

=====================

The APM framework was introduced in Volume Manager 4.0 release. The 4.0 release brought about a major change in DMP architecture - the introduction of APM. As the name suggests, the Array Policy Module (APM) is specific to an array type and defines the policies for an array type. Analogous to its Array Support Library (ASL) counterpart in user space which enables the DDL to identify the array completely, the APM enables DMP kernel to perform array specific operations such as failover, NDU (Non-Disruptive Upgrade), STPG (Set Target Port Groups) and even an I/O policy.

The APM makes it possible for DMP to dynamically add kernel support for an array. The support for enabling an APM is completely online and does not require a reboot. An APM is essentially a dynamically loadable kernel module that is validated and loaded by DMP whenever DMP detects the array type support exported by that APM. In other words, the DDL...

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Device Discovery in DMP
Ameya | 10 Dec 2010 | 1 comment

The first basic function for a multi path (MP) driver is to identify the set of block devices that can be supported. The device discovery is generally triggered when the MP driver is loaded into the operating system (OS) as part of boot process. During early boot, not all devices connected to the system may be available. For example, the devices connected using the fibre channel (FC) cables may not be available during early boot time unless there is special support from the bootstrap, which is usually from NVRAM or EEPROM, to identify the fibre channel devices. In any case, it may be required for a MP driver to rescan the OS device tree at a later stage of boot process.

One of the biggest challenges in device discovery is the ability and skill of MP driver to discover disk devices and their attributes in a non-intrusive fashion such that the disk media is not touched. In other words, the device discovery has to be purely read-only operations to identify the disk and disk...

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Dynamic Multi Path (DMP) - Historical Perspective and Evolution
Ameya | 10 Dec 2010 | 0 comments

The Dynamic Multi Path (DMP) capability was first introduced in Volume Manager 2.5.7 release primarily to support A/A multi path arrays from Sun Microsystems. In those days, the early version of arrays had SCSI connections with fat and thick cables running from host to the array directly. Unlike the present day modern arrays, there was no concept of fabric switches, and no fiber channel (FC) technology enabled on the arrays. The first DMP could do only multi path operations such as load balancing using balanced path I/O policy, path failures and restoration by using SCSI inquiry commands. Since the number of devices were handful, the error processing and restore processing were all single threaded tasks. Further, as the number of supported arrays was small, the entire device discovery and reconfiguration was closely tied to the parent operating system.

The next major enhancements of DMP were introduced in Volume Manager 3.1.1 release that had support to co-exist with...

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