Red Hat GLOBAL FILE SYSTEM 5.2 Guida di Installazione

Global File SystemRed Hat Global FileSystem5.2Global_File_SystemISBN: N/APublication date: May 2008

Bugzilla component: Documentation-clusterBook identifier: Global_File_System(EN)-5.2 (2008-05-21T15:10)By mentioning this manual's identifier, we

GFS OverviewThe Red Hat GFS file system is a native file system that interfaces directly with the Linux kernelfile system interface (VFS layer). A GFS

1. New and Changed FeaturesThis section lists new and changed features included with the initial release of Red HatEnterprise Linux 5.• GULM (Grand Un

The GFS SAN configuration in Figure 1.1, “GFS with a SAN” provides superior file performancefor shared files and file systems. Linux applications run

Figure 1.2. GFS and GNBD with a SANFigure 1.3, “GFS and GNBD with Directly Connected Storage” shows how Linux clientapplications can take advantage of

Figure 1.3. GFS and GNBD with Directly Connected Storage3. GFS Software ComponentsTable 1.1, “GFS Software Subsystem Components” summarizes the GFS so

4. Before Setting Up GFSBefore you install and set up GFS, note the following key characteristics of your GFS filesystems:GFS nodesDetermine which nod

Getting StartedThis chapter describes procedures for initial setup of GFS and contains the following sections:• Section 1, “Prerequisite Tasks”• Secti

2. Create GFS file systems on logical volumes created in Step 1. Choose a unique name foreach file system. For more information about creating a GFS f

Managing GFSThis chapter describes the tasks and commands for managing GFS and consists of thefollowing sections:• Section 1, “Creating a File System”

This book provides information about installing, configuring, and maintaining Red Hat GFS (RedHat Global File System) for Red Hat Enterprise Linux 5.2

system options.UsageWhen creating a clustered GFS filesystem, you can use either of the following formats:gfs_mkfs -p LockProtoName -t LockTableName -

required for each node that mounts the file system. (More journals than are needed can bespecified at creation time to allow for future expansion.)Blo

gfs_mkfs -p lock_dlm -t alpha:mydata2 -j 8 /dev/vg01/lvol1mkfs -t gfs -p lock_dlm -t alpha:mydata2 -j 8 /dev/vg01/lvol1Complete OptionsTable 3.1, “Com

Flag Parameter Description-t LockTableNameUsed in a clustered file system. This parameter hastwo parts separated by a colon (no spaces) asfollows: Clu

-o aclGFS-specific option to allow manipulating file ACLs.BlockDeviceSpecifies the block device where the GFS file system resides.MountPointSpecifies

Option Descriptionignore_local_fsCaution: This option should not be usedwhen GFS file systems are shared.file system. By default, using lock_nolockaut

3. Unmounting a File SystemThe GFS file system can be unmounted the same way as any Linux file system — by using theumount command.NoteThe umount comm

gfs_tool gettune MountPointMountPointSpecifies the directory where the GFS file system is mounted.ExamplesIn this example, all GFS tunable parameters

statfs_fast = 05. GFS Quota ManagementFile-system quotas are used to limit the amount of file system space a user or group can use. Auser or group doe

gfs_quota warn -g Group -l Size -f MountPointUserA user ID to limit or warn. It can be either a user name from the password file or the UIDnumber.Grou

Global File System: Red Hat Global File SystemCopyright © 2008 Red Hat, Inc.Copyright © 2008 Red Hat, Inc. This material may only be distributed subje

gfs_quota get -u User -f MountPointDisplaying Quota Limits for a Groupgfs_quota get -g Group -f MountPointDisplaying Entire Quota Filegfs_quota list -

The hard limit set for the user or group. This value is zero if no limit has been set.ValueThe actual amount of disk space used by the user or group.C

You can use the gfs_quota sync command to synchronize the quota information from a nodeto the on-disk quota file between the automatic updates perform

enforcement is done by changing a tunable parameter, quota_enforce, with the gfs_toolcommand. The quota_enforce parameter must be disabled or enabled

quota_account tunable parameter to 0. This must be done on each node and after each mount.(The 0 setting is not persistent across unmounts.) Quota acc

# gfs_tool settune /gfs quota_account 1# gfs_quota init -f /gfs6. Growing a File SystemThe gfs_grow command is used to expand a GFS file system after

After running the gfs_grow command, you can run a df MountPoint command on the filesystem to check that the new space is now available in the file sys

7. Adding Journals to a File SystemThe gfs_jadd command is used to add journals to a GFS file system after the device where thefile system resides has

SB multihost format = 1401Block size = 4096Journals = 8Resource Groups = 76Mounted lock proto = "lock_dlm"Mounted lock table = "tng3-cl

Complete Usagegfs_jadd [Options] {MountPoint | Device} [MountPoint | Device]MountPointSpecifies the directory where the GFS file system is mounted.Dev

Global File System

Direct I/O is a feature of the file system whereby file reads and writes go directly from theapplications to the storage device, bypassing the operati

FileSpecifies the file where the directio flag is assigned.ExampleIn this example, the command sets the directio flag on the file named datafile in di

DirectorySpecifies the directory where the inherit_directio flag is set.ExampleIn this example, the command sets the inherit_directio flag on the dire

gfs_tool setflag inherit_jdata Directorygfs_tool clearflag inherit_jdata DirectorySetting and Clearing the jdata Flaggfs_tool setflag jdata Filegfs_to

Each file inode and directory inode has three time stamps associated with it:• ctime — The last time the inode status was changed• mtime — The last ti

10.2. Tune GFS atime QuantumWhen atime updates are enabled, GFS (by default) only updates them once an hour. The timequantum is a tunable parameter th

UsageStart Suspensiongfs_tool freeze MountPointEnd Suspensiongfs_tool unfreeze MountPointMountPointSpecifies the file system.ExamplesThis example susp

MountPointSpecifies the file system to which the action applies.ExampleThis example reports extended file system usage about file system /mnt/gfs.[roo

The number of gfs_glock structures that currently exist in gfs.locks heldThe number of existing gfs_glock structures that are not in the UNLOCKED stat

glocks reclaimedThe number of glocks which have been reclaimed.glock dq callsThe number of glocks released since the file system was mounted.glock pre

Introduction ... vii1. Audience ...

MountPointSpecifies the file system to which the action applies.ExampleThis example reports statistics about the file system mounted at /mnt/gfs.[root

NoteThe information that the gfs_tool stat command displays reflects internal filesystem information. This information is intended for development pur

di_entries = 0no_formal_ino = 0no_addr = 0di_eattr = 0di_reserved =00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0000 00 00 00 00 00 00 00 00 00 00 00

other command options.Usagegfs_fsck -y BlockDevice-yThe -y flag causes all questions to be answered with yes. With the -y flag specified, thegfs_fsck

Starting pass1cLooking for inodes containing ea blocks...Pass1c completeStarting pass2Checking directory inodes.Pass2 completeStarting pass3Marking ro

VariableSpecifies a special reserved name from a list of values (refer to Table 3.5, “CDPN VariableValues”) to represent one of multiple existing file

n01# cd /gfsn01# mkdir n01 n02 n03n01# ln -s @hostname logn01# ls -l /gfslrwxrwxrwx 1 root root 9 Apr 25 14:04 log -> @hostname/drwxr-xr-x 2 root r

IndexAadding journals to a file system, 27atime, configuring updates, 33mounting with noatime, 34tuning atime quantum, 35audience, viiCCDPN variable v

Iinitial taskssetup, initial, 7introduction, viiaudience, viiMmanaging GFS, 9maximum size, GFS file system, 1, 6mount table, 14mounting a file system,

vi

IntroductionThe Global File System Configuration and Administration document provides information aboutinstalling, configuring, and maintaining Red Ha

• Using GNBD with Global File System — Provides an overview on using Global Network BlockDevice (GNBD) with Red Hat GFS.• Linux Virtual Server Adminis

Additionally, the manual uses different strategies to draw your attention to pieces of information.In order of how critical the information is to you,