AIX Workload Partions Viraf Patel virafus ibm com

AIX Workload Partions Ø Viraf Patel Ø viraf@us. ibm. com © 2008 IBM Corporation

IBM Systems Group Agenda Ø Introduction to AIX Workload Partitions (WPAR) Ø WPAR characteristics and positioning Ø System WPARs Ø Application WPARs Ø WPAR administration Ø WPAR Performance Tools Ø Summary 2 © 2008 IBM Corporation

IBM Systems Group What are AIX Workload Partitions? Ø Created via software as virtualized environments in a single AIX instance Ø Partitioned system capacity AIX Image ü Each Workload Partition obtains a regulated share of the processor and memory resources ü Each Workload Partition has separate network and filesystems and many system services (e. g. telnetd, etc. ) Ø Separate Administrative control ü Each Workload partition is a separate administrative and security domain Ø Shared system resources ü I/O Devices Workload Partition App Svr Workload Partition Web Svr Workload Partition Billing Svr Workload Partition Test Svr Workload Partition E ü Processor ü Operating system ü Shared Library and Text 3 © 2008 IBM Corporation

IBM Systems Group Benefits of IBM AIX Workload Partitions Ø reduced administration expense by leveraging a single AIX image Ø drive higher system utilization Ø reduce the number of system images to maintain Ø “good enough” isolation for many workloads Sys 3 Application A Application B Application C Single System or LPAR AIX Partition #1 Sys 2 Sys 1 AIX Partition #2 AIX Partition #3 4 © 2008 IBM Corporation

IBM Systems Group AIX Workload Partitions can be used in LPARs Dedicated Processor LPAR Finance Planning Micro. Partition Processor Pool LPAR Americas WPAR #1 MFG WPAR #1 Bus Dev VIO Server LPAR Asia LPAR EMEA WPAR #1 e. Mail WPAR #2 Test WPAR #2 Planning WPAR #3 Billing POWER Hypervisor 5 © 2008 IBM Corporation

IBM Systems Group IBM System p 5 Flexible Resource Management Ease of Administration AIX Workload Partitions complement System p 5 Logical Partitions AIX Workload Partitions Micro. Partition LPAR Dedicated Processor LPAR Workload Manager Workload Isolation 6 © 2008 IBM Corporation

IBM Systems Group WPAR Implications ØWhat workloads to use on WPARs? Need for dedicated I/O resources ü Isolation and security ü ØSecurity/backup/management standards for WPARs ØWhen to use Application WPARs versus System WPARs 7 © 2008 IBM Corporation

IBM Systems Group Technologies for server consolidation pain points Pain point Client workload requires the maximum amount of isolation between workloads on a single server 8 AIX Technology Micro. Partitions Client needs to consolidate multiple workloads on a single system for highest efficiency Micro. Partitions or Workload Partitions Client needs to consolidate multiple workloads on a single system for highest efficiency and minimize the number of AIX operating systems to manage Workload Partitions Client needs to consolidate multiple workloads on a single system for highest efficiency and maximize the flexibility to support different environments Micro. Partitions Client needs to balance workloads by relocating workloads between systems Partition Mobility or Application Mobility Client needs to balance workloads by relocating workloads between systems with minimum delay Partition Mobility Client needs automatic, policy based relocation of workloads between systems Application Mobility © 2008 IBM Corporation

IBM Systems Group When to use Workload Partitions Requirement Hardware enforced Isolation Micro. Partitions x Minimal number of AIX images 9 Workload Partitions x Server Consolidation x x Greatest Flexibility x Cross system workload management x x Move workload between systems x x © 2008 IBM Corporation

IBM Systems Group WPAR Terminology ØGlobal environment ØCheckpoint and restart ØMobility ØDeparture system ØArrival

IBM Systems Group WPAR Types ØThere are 2 types of WPARS System WPAR ü Application WPAR ü ØBoth WPAR type can be configured for mobility via the AIX Workload Partition Manager product 11 © 2008 IBM Corporation

IBM Systems Group Characteristics of WPARs ØDevices Managed and administered in the global environment ü Support pseudo-devices in WPARs ü ØNetworking Support multiple addresses for login and network services ü WPARs IP address is aliased to IP address in the global environment ü Configurable at creation time or later ü ØSecurity Limited interaction with global environment ü Limited interaction with persistent objects ü 12 © 2008 IBM Corporation

IBM Systems Group Characteristics of WPARs ØWPAR isolation System WPARs and application WPARs are isolated from each other ü System WPARs are integrated with AIX RBAC facility which is not true for Application WPARs ü ØResource Control Ability to change resources dynamically within a WPAR ü Allows share based allocation or percentage based allocation for processor and memory resources ü 13 © 2008 IBM Corporation

IBM Systems Group Devices in a WPAR ØUnavailable /dev/mem ü /dev/nvram ü ØStorage available from global environment via a mounted file system ØNetwork addressing through IP address aliasing from the global environment 14 © 2008 IBM Corporation

IBM Systems Group WPAR filesystem ØSystem WPAR localized view of filesystem ü ü ü / /usr /opt /tmp /var /home Ø 3 primary forms of file system access ü Shared-system – ü nfs hosted – ü Set of fs’s which can include /usr and /opt mounted ro or rw via a nfs host server Non-shared – 15 /usr and /opt are shared read-only from the global environment via namefs mounts /usr and /opt are separate local filesystems (jfs/jfs 2) within the WPAR © 2008 IBM Corporation

IBM Systems Group Specification file ØTo use a specification file to create a system WPAR ü mkwpar -f /tmp/specfile 1 ØTo create a specification file as part of the WPAR creation process ü mkwpar -n wpar_name -o /tmp/specfile ØTo generate a specification file without creating the WPAR, mkwpar -o /tmp/specfile 3 -w Ø/usr/samples/wpars/sample. spec file. 16 © 2008 IBM Corporation

IBM Systems Group Resource Control of WPARs ØTo initialize resource control settings, run the following mkwpar command ü mkwpar -n wpar_name -R active=yes CPU=10%-20%, 50% total. Processes=1024 – – A minimum of 10% of the global environment’s processors upon request A maximum of 20% of the global environment’s processors when there is contention A maximum of 50% of the global environment’s processors when there is no contention A maximum of 1024 processes at a time ØChange resource control settings dynamically for an existing active or inactive application WPAR chwpar -R total. Threads=2048 shares_memory=100 wpar_name ü chwpar –R shares_CPU=70 wpar_name ü chwpar –R CPU=5%-20%, 50% wpar_name ü 17 © 2008 IBM Corporation

IBM Systems Group Resource Control of WPARs ØUnderstanding CPU shares ü ü ü wpar A has 4 shares, wpar B has 8 shares, wpar C has 12 shares total shares=4+8+12=24 allocation would be wpar A = 4/24=16. 6% , B=8/24=33. 3%, C=12/24=50% If another wpar is added shares would alll be adjusted added wpar D 6 shares wpar A =4/30=13. 3% …. . wpar D = 6/30=20%. . wpar C=12/30=40% ØMemory shares operate similarly ØBy default number of shares for each WPAR is unlimited 18 © 2008 IBM Corporation

IBM Systems Group Listing Resource of WPARs ØCPU shares – (lswpar –L edited output) RESOURCE CONTROLS Active: Resource Set: CPU Shares: CPU Limits: Memory Shares: Memory Limits: Per-Process Virtual Memory Limit: Total Processes: Total Threads: 19 yes unlimited 0%-100%, 100% unlimited © 2008 IBM Corporation

IBM Systems Group Attributes before creating system WPAR root@ec 10 (/) > oslevel -s 6100 -00 -03 -0808 root@ec 10 (/) > uname -nu. ML ec 10 IBM, 9117 -MMA IBM, 02109 A 4 AF 12 ec 10_aix_wpar root@ec 10 (/) > df -k Filesystem 1024 -blocks Free %Used Iused %Iused Mounted on /dev/hd 4 131072 18920 86% 7736 61% / /dev/hd 2 1703936 158400 91% 33809 47% /usr /dev/hd 9 var 131072 9280 93% 5235 64% /var /dev/hd 3 131072 130296 1% 33 1% /tmp /dev/hd 1 131072 130688 1% 7 1% /home /dev/hd 11 admin 131072 130708 1% 5 1% /admin /proc - - - /proc /dev/hd 10 opt 262144 113744 57% 2888 11% /opt /dev/fslv 00 1048576 940096 11% 21 1% /wpcode ØCan create WPARs using specification file or image. data file ümkwpar –o /tmp/spec 1 –w (generate specification file) ümkwpar –I image. data file –n wpar_name 20 © 2008 IBM Corporation

IBM Systems Group Attributes before creating system WPAR root@ec 10 (/) > netstat -ni Name Mtu Network Address Zone. ID Ipkts Ierrs Opkts Oerrs Coll en 0 1500 link#2 4 e. c 4. 33. 6. 45. 2 11255767 0 2884729 0 0 en 0 1500 9. 19. 51. 137 11255767 0 2884729 0 0 lo 0 16896 link#1 1895 0 3398 0 0 lo 0 16896 127. 0. 0. 1 1895 0 3398 0 0 lo 0 16896 : : 1 0 1895 0 3398 0 0 root@ec 10 (/) > ifconfig en 0: flags=1 e 080863, 480<UP, BROADCAST, NOTRAILERS, RUNNING, SIMPLEX, MULTICAST, GROUPT 64 BIT, CHECKSUM_OFFLOAD(ACTIVE), CHAIN> inet 9. 19. 51. 137 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 tcp_sendspace 262144 tcp_recvspace 262144 rfc 1323 Note : - you can edit /etc/hosts and insert entry for new WPARs - you can use clogin from global environment to access wpar 21 © 2008 IBM Corporation

IBM Systems Group Creating System WPAR root@ec 10 (/) > lswpar Name State Type Hostname Directory --------------------wp 04 A A wp 04 / root@ec 10 (/) > mkwpar -n wp 03 mkwpar: Creating file systems. . . / /home /opt /proc /tmp /usr /var ………… mkwpar: Workload partition wp 03 created successfully. To start the workload partition, execute the following as root: startwpar [-v] 'ec 09‘ root@ec 10 (/) > startwpar -v wp 03 Starting workload partition wp 03. Invalid Script File. . . Mounting all workload partition file systems root@ec 10 (/usr/local) > lswpar Name State Type Hostname Directory --------------------wp 03 A S wp 03 /wpars/wp 03 wp 04 A A wp 04 / 22 © 2008 IBM Corporation

IBM Systems Group rootvg – before WPAP is created root@sq 18 (/wpars) > du

IBM Systems Group rootvg after WPAR is created root@sq 18 (/) > du -k

IBM Systems Group Creating WPAR on P 5 system root@ec 10 (/) > lswpar root@ec 10 (/) > mkwpar -n wp 03 mkwpar: Creating file systems. . . / /home /opt /proc /tmp /usr /var ………. mkwpar: Workload partition wp 03 created successfully. To start the workload partition, execute the following as root: startwpar [-v] ‘wp 03` real 3 m 57. 74 s user 1 m 30. 02 s sys 0 m 48. 23 s root@ec 10 (/) > clogin ec 20 Workload partition wp 03 is not active. root@ec 10 (/) > startwpar -v wp 03 Starting workload partition subsystem cor_wp 03 Return Status = SUCCESS root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 20 A S ec 20 /wpars/ec 20 root@ec 10 (/) > clogin wp 03 ************************************************* * * * Welcome to AIX Version 6. 1! * * * Please see the README file in /usr/lpp/bos for information pertinent to * * this release of the AIX Operating System. * * ************************************************** 25 © 2008 IBM Corporation

IBM Systems Group Creating WPAR on a P 6 system # lswpar Name State Type Hostname Directory --------------------wp 04 D S wp 04 /wpars/wp 04 # time mkwpar -n wp 04 mkwpar: Creating file systems. . . / /home /opt /proc /tmp /usr /var ……………… mkwpar: Workload partition wp 04 created successfully. To start the workload partition, execute the following as root: startwpar [-v] `wp 04' real 4 m 0. 22 s user 1 m 4. 13 s sys 0 m 37. 17 s 26 © 2008 IBM Corporation

IBM Systems Group Creating WPAR on a P 6 system - SMIT 27 ©

IBM Systems Group Creating WPAR on a P 6 system – Systems Director AIX

IBM Systems Group Starting WPARs # startwpar -v ec 09 Starting workload partition ec 09. Invalid Script File. . . Mounting all workload partition file systems. Mounting /wpars/ec 09/home. Mounting /wpars/ec 09/opt. Mounting /wpars/ec 09/proc. Mounting /wpars/ec 09/tmp. Mounting /wpars/ec 09/usr. Mounting /wpars/ec 09/var. Loading workload partition. $corral_t = { 'vips' => [ [ 'en 0', '9. 19. 51. 136', '255. 0', '9. 19. 51. 255' ] ], 'opts' => 4, 'name' => 'ec 09', 'path' => '/wpars/ec 09', 'hostname' => 'ec 09', 'id' => 0, 'key' => 7 }; Exporting workload partition devices. Starting workload partition subsystem cor_ec 09. 0513 -059 The cor_ec 09 Subsystem has been started. Subsystem PID is 405548. Verifying workload partition startup. Return Status = SUCCESS. 30 © 2008 IBM Corporation

IBM Systems Group Viewing WPARs from global environment root@sq 18 (/) > cd /wpars root@sq 18 (/) > ls ec 08 ec 09 root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 09 A S ec 09 /wpars/ec 09 ec 10 A S ec 10 /wpars/ec 10 ec 11 A S ec 11 /wpars/ec 11 31 © 2008 IBM Corporation

IBM Systems Group Viewing WPARs filesystems from global environment root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 09 A S ec 09 /wpars/ec 09 ec 10 T A ec 10 / ec 12 A S ec 12 /wpars/ec 12 root@sq 18 (/) > df -k Filesystem 1024 -blocks Free %Used Iused %Iused Mounted on /dev/hd 4 131072 69524 47% 1820 9% / /dev/hd 2 1703936 283080 84% 33479 34% /usr /dev/hd 9 var 196608 183652 7% 452 2% /var /dev/hd 3 196608 195804 1% 38 1% /tmp /dev/hd 1 917504 917000 1% 7 1% /home /proc - - - /proc /dev/hd 10 opt 786432 730492 8% 1108 1% /opt /dev/fslv 00 2097152 1394432 34% 482 1% /0728 a /dev/fslv 01 65536 46372 30% 1631 14% /wpars/ec 12 /dev/fslv 02 65536 64136 3% 7 1% /wpars/ec 12/home /opt 786432 730492 8% 1108 1% /wpars/ec 12/opt /proc - - - /wpars/ec 12/proc /dev/fslv 03 131072 128348 3% 13 1% /wpars/ec 12/tmp /usr 1703936 283080 84% 33479 34% /wpars/ec 12/usr /dev/fslv 04 131072 118728 10% 395 2% /wpars/ec 12/var /dev/fslv 05 65536 46964 29% 1631 14% /wpars/ec 09 /dev/fslv 06 65536 64136 3% 7 1% /wpars/ec 09/home /opt 786432 730492 8% 1108 1% /wpars/ec 09/opt /proc - - - /wpars/ec 09/proc /dev/fslv 07 131072 128348 3% 13 1% /wpars/ec 09/tmp /usr 1703936 283080 84% 33479 34% /wpars/ec 09/usr /dev/fslv 08 131072 118756 10% 396 2% /wpars/ec 09/var 32 © 2008 IBM Corporation

IBM Systems Group WPAR listing and ip address aliasing view lswpar Name State Type Hostname Directory --------------------ec 09 A S ec 09 /wpars/ec 09 ec 10 A S ec 10 /wpars/ec 10 netstat -ni Name Mtu Network Address Zone. ID Ipkts Ierrs Opkts Oerrs Coll en 0 1500 link#2 0. 9. 6 b. dd. 43. ba 3119936 0 433744 4 0 en 0 1500 9. 19. 51. 54 3119936 0 433744 4 0 en 0 1500 9. 19. 51. 136 8909 0 10740 0 0 en 0 1500 9. 19. 51. 137 1067 0 2045 0 0 lo 0 16896 link#1 20997 0 21007 0 0 lo 0 16896 127. 0. 0. 1 20997 0 21007 0 0 lo 0 16896 : : 1 0 20997 0 21007 0 ifconfig en 0: flags=5 e 080863, c 0<UP, BROADCAST, NOTRAILERS, RUNNING, SIMPLEX, MULTICAST, GROUPR T, 64 BIT, CHECKSUM_OFFLOAD(ACTIVE), PSEG, LARGESEND, CHAIN> inet 9. 19. 51. 54 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 inet 9. 19. 51. 136 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 inet 9. 19. 51. 137 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 tcp_sendspace 131072 tcp_recvspace 65536 lswpar -N ec 08 Name Interface Address Netmask Broadcast ----------------------------ec 08 en 0 9. 19. 51. 154 255. 0 9. 19. 51. 255 33 © 2008 IBM Corporation

IBM Systems Group Application WPARs ØProvide path to the application or command that requires the application WPAR ØUse specification file or command line argument ØNot necessary to specify WPAR name explicitly at creation 34 © 2008 IBM Corporation

IBM Systems Group Creating Application WPARs root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 12 A S ec 12 /wpars/ec 12 root@sq 18 (/) > wparexec -n ec 10 /usr/local/loadgen -t 10 /usr/bin/ps –ef > ps. out wparexec: Verifying file systems. . . wparexec: Workload partition ec 10 created successfully. Invalid Script File. . . root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 10 A A ec 10 / ec 12 A S ec 12 /wpars/ec 12 root@sq 18 (/) > clogin ec 10 root@ec 10 (/) > uname -a AIX ec 10 1 6 00 C 1677 E 4 C 00 35 © 2008 IBM Corporation

IBM Systems Group Application WPAR listing and ip address aliasing view root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 10 A A ec 10 / ec 12 A S ec 12 /wpars/ec 12 root@sq 18 (/) > netstat -ni Name Mtu Network Address Zone. ID Ipkts Ierrs Opkts Oerrs Coll en 0 1500 link#2 0. 9. 6 b. dd. 43. ba 5196841 0 569426 4 0 en 0 1500 9. 19. 51. 54 5196841 0 569426 4 0 en 0 1500 9. 19. 51. 139 1540 0 1073 0 0 en 0 1500 9. 19. 51. 137 9 0 0 lo 0 16896 link#1 91272 0 91289 0 0 lo 0 16896 127. 0. 0. 1 91272 0 91289 0 0 lo 0 16896 : : 1 0 91272 0 91289 0 0 root@sq 18 (/) > ifconfig en 0: flags=5 e 080863, c 0<UP, BROADCAST, NOTRAILERS, RUNNING, SIMPLEX, MULTICAST, GROUPRT, 64 BIT, CHEC KSUM_OFFLOAD(ACTIVE), PSEG, LARGESEND, CHAIN> inet 9. 19. 51. 54 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 inet 9. 19. 51. 139 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 inet 9. 19. 51. 137 netmask 0 xffffff 00 broadcast 9. 19. 51. 255 tcp_sendspace 131072 tcp_recvspace 65536 36 © 2008 IBM Corporation

IBM Systems Group Removing WPARs # rmwpar ec 09 rmwpar: Workload partition 'ec 09' is running. rmwpar: Specify -s or -F to stop the workload partition before removing. rmwpar: Return Status = FAILURE # rmwpar A workload partition name must be specified. Usage: rmwpar [-F] [-p] [-s] wpar. Name Flags: -F = Forced remove. The '-s' flag is implied. -p = Preserve file systems (system workload partitions only). -s = Stops the workload partition before removing (system workload partitions only - application workload partitions should use the stopwpar command). 37 © 2008 IBM Corporation

IBM Systems Group Removing WPARs # rmwpar -s ec 09 rmwpar: Removing workload partition ec 09 rmwpar: Stopping workload partition ec 09. Stopping workload partition subsystem cor_ec 09. 0513 -044 The cor_ec 09 Subsystem was requested to stopwpar: 0960 -261 Waiting up to 600 seconds for workload partition to halt. Advanced Accounting is not running. stopwpar: 0960 -231 ATTENTION: /usr/lib/wpars/wparinstcmd failed with return code 1. Shutting down all workload partition processes. 38 © 2008 IBM Corporation

IBM Systems Group Removing WPARs # rmwpar -F ec 09 rmwpar: Removing workload partition ec 09 rmwpar: Stopping workload partition ec 09 stopwpar: 0960 -254 Workload partition ec 09 is not currently active. rmwpar: Removing file system /wpars/ec 09/var. rmlv: Logical volume fslv 08 is removed. rmwpar: Removing file system /wpars/ec 09/usr. rmwpar: Removing file system /wpars/ec 09/tmp. rmlv: Logical volume fslv 07 is removed. rmwpar: Removing file system /wpars/ec 09/proc. rmwpar: Removing file system /wpars/ec 09/opt. rmwpar: Removing file system /wpars/ec 09/home. rmlv: Logical volume fslv 06 is removed. rmwpar: Removing file system /wpars/ec 09. rmlv: Logical volume fslv 05 is removed. rmwpar: Return Status = SUCCESS # lswpar Name State Type Hostname Directory --------------------ec 08 D S ec 08 /wpars/ec 08 39 © 2008 IBM Corporation

IBM Systems Group WPAR administration – backup and restore ØWPARs are backed up using the “mkwpardata” command ØImage files are generated using the “savewpar” command root@sq 18 (/) > lswpar Name State Type Hostname Directory --------------------ec 12 A S ec 12 /wpars/ec 12 root@sq 18 (/) > savewpar ec 12 0512 -057 savewpar: Device /dev/rmt 0 is not in the available state or is not a tape device or valid file name. ØWPARs are restored using “restwpar” command root@sq 18 (/) > restwpar -f /dev/rmt 1 40 © 2008 IBM Corporation

IBM Systems Group Tools available within WPAR # ps PID TTY TIME CMD 335920 pts/0 0: 00 -ksh 491650 pts/0 0: 00 ps # wlmstat CLASS CPU MEM DKIO ec 12 0. 45 0. 41 0. 00 TOTAL 0. 45 0. 41 0. 00 # df Filesystem 512 -blocks Free %Used Iused %Iused Mounted on /dev/fslv 01 131072 93472 29% 1632 14% / /dev/fslv 02 131072 128272 3% 7 1% /home /opt 1572864 1460984 8% 1108 1% /opt /proc - - - /proc /dev/fslv 03 262144 256696 3% 13 1% /tmp /usr 3407872 566160 84% 33479 34% /usr /dev/fslv 04 262144 237464 10% 396 2% /var # users root 41 © 2008 IBM Corporation

IBM Systems Group WPAR monitoring tools ØLimited support for # netstat -i Name Mtu Network Address Zone. ID Ipkts Ierrs Opkts Oerrs Coll en 0 1500 link#2 0. 9. 6 b. dd. 43. ba 3256 0 2207 0 0 en 0 1500 9. 19. 51. 139 3256 0 2207 0 0 lo 0 16896 link#1 1495 0 1525 0 0 lo 0 16896 127 loopback 1495 0 1525 0 0 lo 0 16896 : : 1 0 1495 0 1525 0 0 #w 03: 00 PM up 4: 12, 1 user, load average: 0. 00, 0. 00 User tty login@ idle JCPU PCPU what root pts/0 02: 54 PM 0 4 0 w # svmon size inuse free memory 524288 10541 pg space 131072 1148 pin in use 42 work pers -24581 0 7411 0 pin virtual 175618 130036 148410 clnt other 0 24693 3130 © 2008 IBM Corporation

IBM Systems Group Performance tools for WPARs 43 © 2008 IBM Corporation

IBM Systems Group Topas in WPAR global environment 44 © 2008 IBM Corporation

IBM Systems Group Topas in WPAR environment 45 © 2008 IBM Corporation

IBM Systems Group vmstat in WPAR global environment 46 © 2008 IBM Corporation

IBM Systems Group vmstat in WPAR environment 47 © 2008 IBM Corporation

IBM Systems Group Summary ØWPARs reduce administration expense by leveraging a single AIX image Ø LPARs and WPARs drive higher system utilization and optimize the customers investment Ø WPARs provide dynamic resource allocation capabilities Ø WPARs provide “good enough” isolation for many workloads ØSimple, lightweight, centralized partition administration 48 © 2008 IBM Corporation