Administering Linux in Production Environments 2 Itinerary Administering Linux in § Introduction Production Environments § Production Environment Features • Recent Kernel Developments • Filesystems: Mundane and Advanced • Disk Striping and RAID Administering • Parallel Processing and Clustering Linux in Æleen Frisch Production • Enterprise Networking Features Environments [email protected] § Deployment Examples www.aeleen.com • File and Print Servers • Enterprise User Authentication x Copyright © 1999-2001, e ponential Consulting, LLC Exponential Consulting, LLC • Beowulf Compute Servers North Haven, Connecticut, USA • Linux and Databases • Linux as an Office PC 2 3 4 What is a Production System? Commercial Applications § Real world § Major applications are available now: § System is a tool • Databases: Oracle, Sybase, DB2, etc. § “Money” is involved • Computational chemistry: Gaussian 98 Administering Administering Linux in Linux in • CAE: MSC:Nastran Production Production Environments Environments • Others § Keeping up Copyright © 1999-2001, Copyright © 1999-2001, • www.linas.org/linux Exponential Consulting, LLC Exponential Consulting, LLC • www.linuxports.com 3 4 Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 5 6 Dressing for Success § Tuxedo vs. Business Suit Recent § ILM: 11/15/2001 Administering Administering Kernel Linux in Linux in Production Production Environments Environments Developments Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC 5 6 7 8 2.4 Kernel 2.4: Numbers § Feature Lists: § 64 GB memory • lwn.net/2001/0111/a/wwo2.4.php3 § >2GB files • January 2001 Linux Magazine § 16 Ethernet adapters Administering Administering Linux in Linux in Production Production § 10 IDE controllers Environments Environments § SMP support • Support for tons of processes Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC • Scheduler improvement § Billions of users/groups 7 8 Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 9 10 Current Linux Limitations 2.4: I/O § Modes: § Memory size: 64 GB • Separate block device and file I/O § File size: 2 TB • Raw devices § Devices: § Filesystem size: 2 TB (VFS limitations) • I2O Administering Administering Linux in Linux in • USB Production § Filesystem block size=Memory page Production Environments Environments • Firewire (IEEE1394) • 4KB (x86) • PC Card • 16KB (IA-64) • Infrared Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC§ APCI support § Graphics: Direct rendering manager 9 10 § SCSI2: Tagged command queuing 11 12 2.4: Networking 2.4: VFS and Related Facilities § Better multiprotocol support § Single buffer for file caching § Rewritten network layer (firewalls, • Eliminates synchronization problems IP masquerading): § Multiple mount points Administering Administering Linux in • Packet filtering Linux in Production Production Environments Environments • Network address translation § LVM in kernel § ATM and others § RAID rewrite Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC § Can now mount NFS3 shares Exponential Consulting, LLC 11 12 Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 13 14 2.4 Bonus Features 2.4.1516 § Memory “Management” § ext3 • New swap space size “recommendations” • “experimental” • Fixed around 2.4.10 § InterMezzo filesystem Administering Administering Linux in Linux in Production Production Environments Environments Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC 12.1 13’ 15 16 Itinerary Filesystems: § The VFS § Local Filesystems § Journaling Filesystems Administering Mundane and Administering Linux in Linux in Production Production Environments Advanced Environments § Network Shared Filesystems § Logical Volume Manager Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC § Distributed Filesystems 14 15 Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 17 18 Spelling 101 Virtual File System (VFS) § Filesystem vs. file system § Kernel subsystem/layer § Provides a consistent interface for low-level file I/O Administering Administering Linux in Linux in Production Production Environments Environments § Filesystem need only implement the required functionality using that interface, and it is automatically supported Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC 16 17 19 20 VFS Details FilesystemData Structures § Structured as an indirection layer § Superblock § Specifies low-level entities (objects) ... • FS metadata: label, block size, size, # inodes, … • Inodes, Files, Directories, Superblock, § Inodes Administering Administering Linux in Linux in Production Production Environments • Extended attributes Environments • Properties: file type, owners, permissions, times, #links, size, ... § ... and required/optional methods for each one • Data or Disk addresses or Single/double indirect Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC § Directory 18 19 • = File that maps file names to inodes Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 21 22 VFS in Action 2.4.15+ § Command/application invokes system call § Journal block device module: designed § VFS looks up filesystem type in kernel table to add generic journaling capabilities to the VFS § Kernel redirects call to FS-supplied method Administering Administering Linux in Linux in Production Production Environments § Method runs and accesses disk Environments • Device drivers issue needed I/O requests § Method returns descriptor to desired object Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC • Descriptor contains pointers to functions for accessing that object as well as related data 20 (e.g.: mounted filesystem, file, inode, dentry) 21 23 24 Filesystems for Local Disks Special filesystems § Many, many supported types: § procfs: /proc • ext2 • minix § Pseudo-device: /dev/pts § devfs: Administering • CD-ROM: iso9660, MS Joliet extensions, Administering Linux in Linux in Production v 2.4: udf for DVD Production Environments Environments • /dev/hda => /dev/ide0/disk0/... • ufs, fat, vfat , umsdos, ntfs, sysv , affs, adfs, hfs, • devfsdto support old device names hpfs, qnx4, ... Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC v 2.4: ufs nextstep extensions, efs, ramfs, jffs, cramfs Exponential Consulting, LLC 22 23 Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 25 26 The ext2 Filesystem Ext2 FS Tools § 2GB files and 4TB filesystem § fsck.ext2 § 255 character filenames § mke2fs § SetGID directory group ownership inheritance § e2label Administering Administering Linux in Linux in Production • Selectable at mount time Production § dumpe2fs Environments Environments § Variable block sizes § tune2fs § Performance optimizations: § resize2fs Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC • Read-ahead • Data block allocation and pre-allocation 24 25 27 28 The mke2fs Command dump2efs dumpe2fs 1.18, 11-Nov-1999 for EXT2 FS 0.5b, 95/08/09 Filesystem volume name: <none> Last mounted on: <not available> § -b block-size Filesystem UUID: 03d2f865-390a-4a5a -9162 -8f2fc902d3e2 Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) • Default: 1024 bytes Filesystem features: (none) Filesystem state: not clean Errors behavior: Continue § -i bytes/inode or -N #inodes Filesystem OS type: Linux Administering Administering Inode count: 264928 Linux in • Default: 1 inode per 4096 bytes Linux in Block count: 528948 Production Production Reserved block count: 26447 Environments Environments Free blocks: 260025 § -m reserve% Free inodes: 184468 First block: 0 Block size: 4096 • Default: 5% Fragment size: 4096 Last mount time: Sun Dec 3 09:33:59 2000 Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC Exponential Consulting, LLC Last write time: Mon Jan 29 17:41:57 2001 § -L label Mount count: 12 Maximum mount count: 20 Last checked: Wed Sep 6 18:54:01 2000 § -c or -l bad-block-file Check interval: 15552000 (6 months) Next check after: Mon Mar 5 17:54:01 2001 26 27 Reserved blocks uid : 0 (user root) Ò -f fragment-size Reserved blocks gid : 0 (group root) Copyright © 1999-2001, Exponential Consulting, LLC. All rights reserved. Administering Linux in Production Environments 29 30 The tune2fs Command Contributed ext2 Tools § -l to list superblock info § ext2fs defrag § Modify attributes (mount read-only?) § ext2fs resize • -c max-mounts § ext2fsed Administering Administering Linux in Linux in Production • -C mount-count Production § ext2undelete Environments Environments • -i check-interval[dmw] • -e error-behavior § See: “Filesystems-HOWTO” (section 6) Copyright © 1999-2001, Copyright © 1999-2001, Exponential Consulting, LLC v continue, remount-ro, panic Exponential Consulting, LLC • -m reserved% or -r reserved-blocks 28 • -g gid and/or -u uid 29 31 32 Journaling