emc access logix

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Access LogixLUN Masking in a CLARiiON Environment

LUN Masking is an essential feature of a shared array environment. The administrator can have control over which logical devices (LUNs) are assigned to which host.

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Topics

Access Logix Defined

Storage Group Implementation

Storage Group Troubleshooting

We will be defining Access Logix, examining the steps involved in implementing Access Logix, and examining some key steps in troubleshooting.

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Shared Storage without Access Logix Enabled

0 1 2

3 4 5

6 7 8

Fabric LUNs

HOSTA

HOSTB

HOSTC

0 1 2

3 4 56 7 8

0 1 2

3 4 56 7 8

0 1 2

3 4 56 7 8

Without Access Logix installed on the array, or with in installed-but-not-enabled, All hosts connected to an array will have access to all of the non-private LUNs on the array. In this example, there are 9 LUNs on the array (0-8). Each host on the right (A, B, C) will see all 9 LUNs when the probe for devices.While it is possible to work only with LUNs intended for a certain host, you run the risk of accidentally deleting the data for another host every time you run the UNIX format command, or the Windows Disk Administrator.

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Access Logix Enabled but no Storage Groups Configured

0 1 2

3 4 5

6 7 8

Fabric LUNs

HOSTA

HOSTB

HOSTC

With Access Logix enabled, but no Storage Groups configured, no hosts connected to an array have access to the LUNs on the array. In this example, there are 9 LUNs on the array (0-8). Each host on the right (A, B, C) will see all 0 LUNs when the probe for devices.We will need to create Storage Groups for these hosts in order for them to Access the LUNs designated to them.

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Access Logix Storage Groups Configured

Fabric

HOSTA

HOSTB

HOSTC

Storage Groupfor HOSTC

6 7 8

Storage Groupfor HOSTB

3 4 5

Storage Groupfor HOSTA

0 1 2

012

012

012

With Access Logix installed on the array, and storage groups for all the LUNs and hosts, LUNs will only be visible on their intended hosts, eliminating confusion and the risk of data loss.Here, we have created 3 Storage Groups on the array, and have assigned a set of LUNs and a host to each one. At this point when each host reboots, they will only see the LUNs from their Storage Group. The other LUNs are “masked” from them.Another feature of Access Logix is LUN translation, where it will automatically reassign a LUN number to host so that each host in the SAN will see LUN 0, followed by LUN 1 etc. The LUN numbers on the CLARiiON will remain what they were when bound. You can see the translated LUN numbers in the Host tab of Navisphere Manager.

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Initiator Registration

Fabric

HOSTA

HOSTB

HOSTC

Initiator Database

HOSTA192.168.2.26Win 2000HBA0-WWNHBA1-WWNetc

HOSTB192.168.2.28LINUXHBA0-WWNHBA1-WWNetc

HOSTC192.168.2.30SOLARIS 7HBA0-WWNHBA1-WWNetc

AGENT

AGENT

AGENT

In order to be able to assign a host to a Storage Group, the host must first perform an Initiator Registration. It is a process performed during Agent startup, where the Agent sends information about the host and HBA’s to each array through all paths. Each registration includes:

•sending HBA UID•receiving SP•initiator type•Hostname•other information.

The array uses the information to create a list of hosts to be assigned to Storage Groups.

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Access Logix Installation

Access Logix is array based software

BASE Code comes in two varieties, Without Access Logix (default config), and With Access Logix

To install, replace existing Base code with Access Logix Version

After installed, it’s not enabled by default

Access Logix is not installed by default. After it is installed, it is not automatically enabled.

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Is it Installed & Enabled?

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If you wish to find out if you currently have A/L installed, go to the Software Tab on the Storage System Properties Box in Navisphere. Look at the version of active Base Code. The number following the second decimal point is The Access Logix bit.•0 = NO•1 = YES

Also, Access Logix needs to be enabled before it takes effect. Check the Storage Access Tab, and make sure there is a check next to “Access Control Enabled”.

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Data Access Enabled

When Access Logix is first enabled, all host access to LUNs is disabledYou re-enable host access by creating and configuring Storage Groups. Once Enabled, can be disabled by CLI command or in Engineering Mode through Manager

–Disabling data access can cause data corruption and loss–All data must be backed-up and or removed before disabling

this feature

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Storage Group Creation

To create a Storage Group, right click on the array and select “Create Storage Group” from the menu. Give the Storage Group a name, preferable something which relates it the host which will be attached to it. In order to configure the members of the Storage Group, expand the Storage Groups tree for the newly created Group. Right-click on that item and select Properties.

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Storage Group – Adding LUNs

Select the LUN tab to add the LUNs you wish to access from a particular host. • Show LUNs Lets you select which LUNs will display in the Available LUNs

list. Choices are All or Not in other Storage Groups. • Select LUNs Lets you select LUNs to include in your Storage Group. • Available LUNs Lists all LUNs available to include in the Storage Group where

ID is the ID assigned to the LUN or snapshot when it is bound. Name is the Name you assign to the LUN when it is bound. Capacity is the user capacity of the LUN. Drive Type is Type of disks in the LUN - Fibre Channel or ATA.

• Moves LUNs from Available LUNs to Selected LUNs.• Moves LUNs from Selected LUNs to Available LUNs.

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Storage Groups – Adding Hosts

After selecting the LUNs (or before , it doesn’t matter), select the Host tab. This will be the host you wish to associate with the selected LUNs. If it is a non-clustered host, you should select a single host. If there is a cluster of hosts who are accessing the LUNs, they should all be included under “hosts to be connected”. A HOST CAN BE CONNECTED TO ONLY ONE STORAGE GROUP•Show Hosts Not connected (default) means not in a Storage Group. •Select Hosts Lists all hosts available to connect to the Storage Group • Moves hosts from Available Hosts to Hosts to be connected.• Moves hosts from Hosts to be connected to Available Hosts.•Hosts to be connected Lists all hosts currently connected to this Storage Group.

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Storage Groups - Navisphere

Storage GroupAttached Host(s)LUN(s)Host Device Designation

When you expand the Storage Groups tree in Navisphere you can see all the elements as shown. The Storage Group (HOSTC) is at the top level. Hosts (HOSTC) is listed under hosts. LUNs (LUN 0, LUN 1) are listed under LUNs. Also, in the description of the LUN, we can see the LUNs from the host perspective (c4t1d1). In this example we can see that Flare LUN 0 is appearing on the host as “d1” and Flare LUN 1 is appearing as “d0”. This is evidence of the LUN Aliasing discussed earlier, where the LUN numbers often change from the host perspective.

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Troubleshooting Registration Issues

In this example, an admin found that he could not add a host called “sun111” to his storage group, because it was not listed under “Available Hosts”. The first place to check is the Connectivity Status Window, by right clicking on the array in question.Notice that there is no entry for “sun111” here, rather multiple entries which seems to show the HBA WWN’s from the sun111 host . Also notice that under the header “Registered” there is a string of “No’s”. We will solve this issue by performing a group edit.

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Group Edit

Click on the Group Edit Button from the Connectivity Status Window. Highlight all of the Initiators (WWN-SP Port ID) and move them over to the Selected window by clicking the .

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Group Edit - Filled

After all of the initiators have been moved over to the Selected side, make a couple of other key edits.•Under “New Initiator Information” select the appropriate setting for a particular host/failover type. For basic PowerPath connections from Windows or Sun, you would select CLARiiON Open, Array Commpath Enabled and Failover Mode 1 as shown here. See help file or procedure generator for details on other hosts. •Select “New Host,” type in the Hostname and IP precisely and click OK.

NOTE: If you accidentally add an initiator from a system that already is in a Storage Group, you may cut off access from that host.

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Group Edit - Success

Re-add hosts to Storage Group. Restart Host.

Now we can see a proper registration for the “sun111” host. The server is displayed for the four initiator connections, and it yes under “Fibre” and “Registered”. You will need to add this new entry to the

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Remove an Extraneous Registration

Engineering Mode

TRAINING117TRAINING117TRAINING117TRAINING117

If you see a host listed in the Connectivity Status window, that is no longer attached to the array and is not meant to be attached, you can remove the entry from the initiator database by entering Engineering Mode in Navisphere.Notice that the entries for that host appear as “NO” under the Fibre Column.Highlight the offending records one at a time and click on the New “Deregister” button to remove this record.

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Summary

Access Logix allows for the creation of Storage Groups.

A Storage Group is a LUN-Host table which segments the storage according to customer needs.

The Navisphere interface is used to install and implement Storage Groups

Storage Group Troubleshooting

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