Term
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Definition
| Server. Most Unix hosts and NT/WIN2K |
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Term
| PowerPath Logical Volume can be configured with X paths from storage to host |
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Definition
| 32 paths from storage system to host |
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Term
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Definition
| seamless data migration. Automatic import of Volume Groups, simplifies growth of logical volumes while applications remain online. |
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Term
| PowerPath Automatic Path Failover |
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Definition
| Increases ability of server access to data on Sym and CLAR arrays. Moves I/O workloads across multiple paths. |
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Term
| PowerPath Dynamic Load Balancing |
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Definition
| uses quickest and easiest route or path to access data. |
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Term
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Definition
1) Automatic path failover
2) Dynamic Load balancing (bwtn FA ports)
3) Automatic detect/restore of failed components
4) Online config and mngmnt
5) Common HBA driver support across Sym and CLAR (Emulix)
6) Write Throttling (log files hit at same time as data / tables)
7) Consistency Group support - Sym only (point in time copy across entire system)
8) Logical Volume Manager |
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Term
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Definition
| All Volumes are accessible through all paths |
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Term
| PowerPath directs I/O based on |
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Definition
1) Current workload
2) Path availability |
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Term
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Definition
| placement of I/O requests in the queue (not managing the I/O queues). |
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Term
| PowerPath configures paths as |
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Definition
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Term
| PowerPath Load Balancing Policy: Symm_opt/CLAR-opt (default) |
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Definition
| I/O requests are balanced across multiple paths based on composition of reads, writes, and user-assigned device/app priorities |
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Term
PowerPath Load Balancing Policy:
Round Robbin |
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Definition
| I/O requests are distributed to each available path in turn |
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Term
PowerPath Load Balancing Policy:
Least_I/Os |
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Definition
| I/O requests assigned to path with fewest number of requests in queue |
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Term
PowerPath Load Balancing Policy:
Least_blocks |
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Definition
| I/O requests assigned to path with fewest total blocks in queue |
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Term
PowerPath Load Balancing Policy:
Request |
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Definition
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Term
PowerPath Load Balancing Policy:
No Redirect |
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Definition
| Disable path failover and load balancing. Default for Sym when there is no license; not supported on CLARiiON. Used for upgrades / troubleshooting. |
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Term
PowerPath Load Balancing Policy:
Basic Failover |
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Definition
| Default for CLARiiON when there is no license key; not support on Sym. CDE-type functionality (SP-A - SP-B failover) |
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Term
| CLARiiON back-end employs |
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Definition
| Dual-port disks, redundant FC-AL loops |
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Term
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Definition
| CLARiiON LUN owned by 1 Storage Processor |
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Term
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Definition
| same LUN can be presented and is accessible simultaneously thru multiple front-end ports. |
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Term
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Definition
| occurs on LUN-by-LUN basis. Protects against path fault, HBA fault, and SP fault. |
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Term
| PowerPath CLARiiON Load Balancing |
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Definition
| Balances I/O on host-by-host basis. Across active channels. Only on CLAR FC4700+. Not across SP. |
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Term
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Definition
| CLARiiON Driver Extensions. PowerPath/CLARiiON replaces CDE functionality. Used for non-high availability environments. Has no multi-pathing or load balancing capabilities. |
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Term
| PowerPath and HA Clusters |
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Definition
| PowerPath detects channel failure and uses alternate channels so that cluster software does not have to reconfigure cluster to keep apps running. PowerPath offers load balancing. PowerPath must work cooperatively with cluster software. |
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Term
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Definition
1) Performance and status monitoring
2) Configuration
3) Channel director and path maintenance
4) Restoring path after repair
5) Testing |
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Term
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Definition
PowerPath Volume Manager. Host-resident, logical volume manager (creation/replication).
1) Combines physical disk into Volume Groups (VG)
2) Define "Storage Elements" and physical partitions for Volume Group (VG)
3) Create logical volumes using VG storage elements
4) Presents logical volume to application as physical disk
5) Adjusts storage elements and Volume Groups to support changes in logical volumes |
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