User manual APPLE XSAN 1.0 ADMINISTRATOR GUIDE

[. . . ] Xsan Administrator's Guide Includes information for managing Xsan volumes in a storage area network using Xsan Admin or the command line Apple Computer, Inc. The owner or authorized user of a valid copy of Xsan software may reproduce this publication for the purpose of learning to use such software. No part of this publication may be reproduced or transmitted for commercial purposes, such as selling copies of this publication or for providing paid for support services. The Apple logo is a trademark of Apple Computer, Inc. , registered in the U. S. [. . . ] You can change some storage pool settings in an existing SAN, but other changes require the associated volume to be re-initialized. Renaming a Storage Pool It is possible to rename a storage pool, but doing so erases all data on the storage pool and the volume it belongs to. Warning: When you rename a storage pool, all data on the storage pool and the volume to which it belongs is lost. To rename a storage pool: 1 Unmount the associated volume from all clients. In Xsan Admin, select the volume, click Clients, select clients in the list, and click Unmount. Select the SAN, click Setup, click Storage, and double-click the storage pool in the list. From the Command Line You can also modify a storage pool by modifying the associated volume configuration file in Terminal. For more information, see the cvfs_config man page or "The Volume Configuration File" on page 96. 48 Chapter 3 Managing SAN Storage Setting Storage Pool Access Permissions You can set up storage pools for read-write or read-only access. Changing this setting doesn't damage existing data on the volume. To set storage pool access permissions: 1 In Xsan Admin, select the SAN the storage pool belongs to, click Setup, and click Storage. 3 Choose Read & Write or Read Only from the Permissions pop-up menu. From the Command Line You can also set read or write access to a storage pool using the cvadmin enable command in Terminal. For more information, see the cvadmin man page or "Viewing or Changing Volume and Storage Pool Settings (cvadmin)" on page 85. Choosing the Types of Files Stored on a Storage Pool You can limit the files that are stored on a particular storage pool to volume journal data and metadata, user data, user data with an affinity for that storage pool, or a combination of these. Journal data and metadata are always stored on the first storage pool in a volume. To choose the data types for a storage pool: 1 In Xsan Admin, select the SAN the storage pool belongs to, click Setup, and click Storage. 3 Next to Use For, choose the data types to store on the storage pool. 4 Click OK, then click Save. Chapter 3 Managing SAN Storage 49 Setting Storage Pool Stripe Breadth The default stripe breadth value (64 file system blocks) is adequate for storage pools in most SAN volumes. However, you can adjust this value along with the file system block allocation size to tune SAN performance for special applications. For help choosing a stripe breadth, see "Choosing Stripe Breadth for a Storage Pool, " below. Warning: When you change a storage pool's stripe breadth, all data on the storage pool and the volume to which it belongs is lost. To set the stripe breadth: 1 In Xsan Admin, select the SAN the storage pool belongs to, click Setup, and click Storage. Choosing Stripe Breadth for a Storage Pool Xsan uses the storage pool stripe breadth and volume block allocation size together to decide how to write data to a volume. For most SANs, the default values for storage pool stripe breadth and volume block allocation size result in good performance. [. . . ] metadata Information about a file system and the files it stores (for example, which disk blocks a file occupies or which blocks are available for use). In Xsan, metadata is managed by controllers but stored on SAN volumes. Xsan clients and controllers exchange metadata over an Ethernet connection to avoid interfering with file data, which is transferred over a Fibre Channel connection. mount (verb) To cause an Xsan volume to appear on a client's desktop like any other local disk. [. . . ]