.SAN design reference guide Vol. 1-5 785350-001
Table 124 SVSP inter-site network requirements for long distance gateways (continued)
DescriptionSpecification
150 ms IP network delay one-way or 300 ms round-trip
Maximum latency
1
Must not exceed 0.5% averaged over a 5-minute window
Average packet-loss ratio
2
Must not exceed plus or minus 10% over a 5-minute window
Latency jitter
3
1
Pre-existing restriction
2
A high packet-loss ratio indicates the need to retransmit data across the inter-site link. Each retransmission delays
transmissions queued behind the current packet, thus increasing the time to complete pending transactions.
3
Latency jitter is the difference between the minimum and maximum values, and indicates how stable or predictable the
network delay. The greater the jitter, the greater the variance in the delay, which lowers the performance predictability.
NOTE: Applications typically require more than the minimum bandwidth to meet throughput or
initial full copy requirements. For example, at 10 Mb/s it could take up to two weeks to copy 1
TB of data, longer if the average available bandwidth is less than 10 Mb/s.
Configuration parameters
This section describes general SVSP Configuration parameters. Specific solutions, such as
high-availability clusters, or applications, such as Continuous Access or Business Copy can define
additional configuration parameters or requirements. Solution requirements must be observed as
specified by the solution configuration documentation.
General maximums are as follows:
• Number of servers at 2 HBAs per server (each 2 HBAs will be counted as an additional server)
512 with one DPM group◦
◦ 1024 with two DPM groups
◦ 1536 with three DPM groups
◦ 2048 with four DPM groups
• Number of initiators per FE virtual disk is 64 (32 dual-port hosts)
• Number of paths per Host per FE virtual disk is 8
• FE virtual disks:
4096 with one DPM group◦
◦ 8192 with two DPM groups
◦ 12,288 with three DPM groups
◦ 16,384 with four DPM groups
• BE LUN from a single BE array is 254
• BE LUN from all arrays 1,024
• FE max capacity 16 TB
• BE LUN max capacity 2 TB
• DPM FE paths:
16,384 with one DPM group◦
◦ 32,768 with two DPM groups
Configuration parameters 247