Red Hat ENTERPRISE LINUX 5 - GLOBAL FILE SYSTEM 2 Guida di Installazione Pagina 1

Global File SystemRed Hat Global File System

Chapter 1. GFS OverviewRed Hat GFS is a cluster file system that is available with Red Hat Cluster Suite. Red Hat GFSnodes are configured and managed

2. Performance, Scalability, and EconomyYou can deploy GFS in a variety of configurations to suit your needs for performance, scalabil-ity, and econom

Figure 1.1. GFS with a SAN2.2. Performance, Scalability, Moderate PriceMultiple Linux client applications on a LAN can share the same SAN-based data a

Figure 1.3, “GFS and GNBD with Directly Connected Storage” shows how Linux client applica-tions can take advantage of an existing Ethernet topology to

GFS provides the following main functions:• Making a File System• Mounting a File System• Unmounting a File System• GFS Quota Management• Growing a Fi

Software Subsystem Components Descriptionfile system. This command can also gath-er a variety of information about the filesystem.lock_harness.ko Impl

hostname and IP address of each GNBD server node for setting up GNBD clients later. Forinformation on using GNBD with GFS, see the Using GNBD with Glo

Chapter 2. System RequirementsThis chapter describes the system requirements for Red Hat GFS with Red Hat Enterprise Linux5 and consists of the follow

Fencing is configured and managed in Red Hat Cluster Suite. For more information about fen-cing options, refer to Configuring and Managing a Red Hat C

You can fence GFS nodes with power switches and fencing agents available with Red HatCluster Suite. For more information about fencing with network po

Global File System: Red Hat Global File SystemCopyright © 2007 Red Hat, Inc.This book provides information about installing, configuring, and maintain

Chapter 3. Getting StartedThis chapter describes procedures for initial setup of GFS and contains the following sections:• Section 1, “Prerequisite Ta

scripts, refer to Configuring and Managing a Red Hat Cluster.2. Create GFS file systems on logical volumes created in Step 1. Choose a unique name for

Chapter 4. Managing GFSThis chapter describes the tasks and commands for managing GFS and consists of the follow-ing sections:• Section 1, “Making a F

WarningMake sure that you are very familiar with using the LockProtoName and LockTable-Name parameters. Improper use of the LockProtoName and LockTabl

Flag Parameter Description-b BlockSize Sets the file-system block size to BlockSize. De-fault block size is 4096 bytes.-D Enables debugging output.-h

Table 4.1. Command Options: gfs_mkfs2. Mounting a File SystemBefore you can mount a GFS file system, the file system must exist (refer to Section 1, “

NoteThe mount command is a Linux system command. In addition to using GFS-specificoptions described in this section, you can use other, standard, moun

Option Descriptiontailed troubleshooting information. Use this optionwith care.Note: This option is turned on automatically iflock_nolock locking is s

4.1. Setting QuotasTwo quota settings are available for each user ID (UID) or group ID (GID): a hard limit and awarn limit.A hard limit is the amount

gfs.gfs_quota limit -u Bert -l 1024 -f /gfsThis example sets the warn limit for group ID 21 to 50 kilobytes on file system /gfs.gfs_quota warn -g 21 -

system blocks, respectively.UserA user name or ID to which the data is associated.GroupA group name or ID to which the data is associated.LimitSizeThe

UsageSynchronizing Quota Informationgfs_quota sync -f MountPointMountPointSpecifies the GFS file system to which the actions apply.Tuning the Time Bet

quota_enforce {0|1}0 = disabled1 = enabledCommentsA value of 0 disables enforcement. Enforcement can be enabled by running the command witha value of

NoteInitializing the quota file requires scanning the entire file system and may take along time.ExamplesThis example disables quota accounting on fil

• Back up important data on the file system.• Display the volume that is used by the file system to be expanded by running a gfs_tool dfMountPoint com

6. 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

In this example, the current state of the file system on the /gfs1 directory is checked for the newjournals.gfs_jadd -Tv /gfs1Complete Usagegfs_jadd [

7. Direct I/ODirect I/O is a feature of the file system whereby file reads and writes go directly from the applic-ations to the storage device, bypass

In this example, the command sets the directio flag on the file named datafile in directory /gfs1.gfs_tool setflag directio /gfs1/datafile7.3. GFS Dir

directory (and all its subdirectories). Existing files with zero length can also have data journalingturned on or off.Using the gfs_tool command, data

Table of ContentsIntroduction ...vi1. Audi

every time a file is read, its inode needs to be updated.Because few applications use the information provided by atime, those updates can require asi

be set on each node and each time the file system is mounted. (The setting is not persistentacross unmounts.)UsageDisplaying Tunable Parametersgfs_too

gfs_tool unfreeze MountPointMountPointSpecifies the file system.ExamplesThis example suspends writes to file system /gfs.gfs_tool freeze /gfsThis exam

FileSpecifies the file from which to get information.The gfs_tool command provides additional action flags (options) not listed in this section. Formo

Usagegfs_fsck -y BlockDevice-yThe -y flag causes all questions to be answered with yes. With the -y flag specified, thegfs_fsck command does not promp

Values”) to represent one of multiple existing files or directories. This string is not the nameof an actual file or directory itself. (The real files

drwxr-xr-x 2 root root 3864 Apr 25 14:06 n03/n01# touch /gfs/log/fileAn02# touch /gfs/log/fileBn03# touch /gfs/log/fileCn01# ls /gfs/log/fileAn02# ls

IndexAadding journals to a file system, 26atime, configuring updates, 30mounting with noatime, 31tuning atime quantum, 31audience, viCCDPN variable va

initial taskssetup, initial, 11introduction, viaudience, vireferences, viiiMmaking a file system, 13managing GFS, 13mount table, 17mounting a file sys

9.1. Mount with noatime ...319.2. Tune GFS atime Quantum ...

IntroductionWelcome to the Global File System Configuration and Administration document. This bookprovides information about installing, configuring,

Red Hat Cluster Suite.3. Document ConventionsCertain words in this manual are represented in different fonts, styles, and weights. This high-lighting

ImportantImportant information is necessary, but possibly unexpected, such as a configura-tion change that will not persist after a reboot.CautionA ca

Topic Reference CommentStorage Area Networks(SANs)Designing Storage Area Net-works: A Practical Referencefor Implementing Fibre Chan-nel and IP SANs,