Dell EqualLogic PS6100 series - Page 7

March 2013 Dell EqualLogic Configuration Guide v14.1 vi
6.2
Synchronous replication .................................................................................................................... 6-49
6.2.1 About Synchronous replication ................................................................................................ 6-49
6.2.2 How Synchronous replication works ....................................................................................... 6-49
6.2.3 Synchronous states ..................................................................................................................... 6-50
6.2.4 Caveats: ......................................................................................................................................... 6-50
6.2.5 Requirements for using SyncRep ............................................................................................. 6-50
6.2.6 How SyncRep protects volume availability ............................................................................. 6-51
6.2.7 SyncAlternate volume unavailable ........................................................................................... 6-51
6.2.8 Tracked changes written to the SyncAlternate volume ....................................................... 6-52
6.2.9 SyncActive volume unavailable ................................................................................................. 6-53
6.3 Protecting your EqualLogic group with Internet Protocol Security ........................................... 6-56
6.3.1 Types of protected traffic .......................................................................................................... 6-56
6.3.2 Protected Intra-Group Traffic ................................................................................................... 6-57
6.3.3 IPsec and Replication ................................................................................................................. 6-57
6.3.4 About IPsec Security Parameters.............................................................................................. 6-57
6.3.5 About IPsec Certificates ............................................................................................................. 6-57
6.3.6 About IPsec Pre-Shared Keys .................................................................................................... 6-58
6.3.7 About IPsec policies .................................................................................................................... 6-58
6.3.8 IPsec considerations and limitations ....................................................................................... 6-58
6.3.9 Performance considerations ..................................................................................................... 6-59
6.3.10 Host Connectivity Considerations ........................................................................................... 6-59
7 EqualLogic SAN design............................................................................................................................... 7-60
7.1 General requirements ......................................................................................................................... 7-60
7.1.1 Implementation of standards .................................................................................................... 7-60
7.1.2 General requirements and recommendations ....................................................................... 7-61
7.1.3 Quality of service (qos) ............................................................................................................... 7-62
7.2 Ethernet switches and infrastructure ............................................................................................... 7-62
7.2.1 Connecting SAN switches in a Layer 2 network .................................................................... 7-64
7.2.2 Sizing inter-switch connections ............................................................................................... 7-67
7.2.3 Comparing inter-switch connection types ............................................................................ 7-67
7.3 Building a high-availability SAN ........................................................................................................ 7-68
7.3.1 Design guidelines for host connectivity in a redundant SAN .............................................. 7-69
7.3.2 Multi-path I/O .............................................................................................................................. 7-70
7.3.3 Equallogic iSCI SAN Design ........................................................................................................ 7-71