Dell EqualLogic PS6210XS EqualLogic Host Integration Tools for Linux Version 1 - Page 20

Sysctl Tunables, Ethernet Devices, iSCSI Settings, Logical Volume Management (LVM)

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Sysctl Tunables Sysctl tunables include Network buffer sizes and Multi-NIC settings. The Network buffer size settings are less critical but you should increase these settings to avoid overflowing transmit and receive buffer queues, which can lead to degraded performance. The Multi-NIC settings are critical because they pertain to the ARP Flux and Return Path Filtering issues. Ethernet Devices For every Ethernet device available in the system, the eqltune utility performs a few minor verifications. The most important verification is whether the Generic Receive Offload is enabled or disabled. If the Generic Receive Offload setting is enabled, extremely poor read performance results. Dell recommends you disable this setting. The other Ethernet device settings that the eqltune utility evaluates depend more on the overall network environment than on the host itself. However, you should optimize your network environment settings as suggested by eqltune. iSCSI Settings Similar to sysctl tunables, there are a number of settings in the initiator configuration file that you can adjust for performance gains. The eqltune utility verifies that all discovered nodes are synchronized with the main iscsid.conf file. The Linux iSCSI initiator allows settings to be set per node. However, because these settings are reset when performing a rediscovery, Dell recommends keeping these settings identical to those in iscsid.conf. Logical Volume Management (LVM) The LVM device filter expressions must be set up to exclude hidden Dell EqualLogic DM devices. All LVM configuration settings are in /etc/lvm/lvm.conf. EqualLogic Host Tools This category summarizes whether the running ehcmd process has detected warnings or errors on the running system. For details and an explanation of how to fix these runtime issues, enter ehcmcli status. Examples: eqltune Output This section includes examples of default and verbose outputs from the eqltune command. Example 1: Default eqltune Output When you run eqltune and specify no options, summary information is provided. This information shows the number of issues detected per category by severity level. For example: # eqltune Checking your Linux system for optimal iSCSI performance... Sysctl Tunables Critical Warnings Suggestions Ok ARP Flux 0 0 0 10 RP Filter 0 0 0 5 Network Buffers 0 2 8 0 Scheduler 0 0 1 0 Ethernet Devices eth8 0 0 2 1 eth5 0 0 2 1 eth7 0 0 2 1 eth6 0 0 2 1 eth9 0 0 2 1 20 Installing and Configuring HIT/Linux

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Sysctl Tunables
Sysctl tunables include Network buffer sizes and Multi-NIC settings. The Network buffer size settings are less critical but you should
increase these settings to avoid overflowing transmit and receive buffer queues, which can lead to degraded performance. The Multi-NIC
settings are critical because they pertain to the ARP Flux and Return Path Filtering issues.
Ethernet Devices
For every Ethernet device available in the system, the eqltune utility performs a few minor verifications. The most important verification is
whether the
Generic Receive Offload
is enabled or disabled. If the Generic Receive Offload setting is enabled, extremely poor
read performance results. Dell recommends you disable this setting.
The other Ethernet device settings that the eqltune utility evaluates depend more on the overall network environment than on the host
itself. However, you should optimize your network environment settings as suggested by eqltune.
iSCSI Settings
Similar to sysctl tunables, there are a number of settings in the initiator configuration file that you can adjust for performance gains. The
eqltune utility verifies that all discovered nodes are synchronized with the main
iscsid.conf
file. The Linux iSCSI initiator allows
settings to be set per node. However, because these settings are reset when performing a rediscovery, Dell recommends keeping these
settings identical to those in
iscsid.conf
.
Logical Volume Management (LVM)
The LVM device filter expressions must be set up to exclude hidden Dell EqualLogic DM devices. All LVM configuration settings are
in
/etc/lvm/lvm.conf
.
EqualLogic Host Tools
This category summarizes whether the running ehcmd process has detected warnings or errors on the running system. For details and an
explanation of how to fix these runtime issues, enter
ehcmcli status
.
Examples: eqltune Output
This section includes examples of default and verbose outputs from the
eqltune
command.
Example 1: Default eqltune Output
When you run
eqltune
and specify no options, summary information is provided. This information shows the number of issues detected
per category by severity level. For example:
# eqltune
Checking your Linux system for optimal iSCSI performance...
Sysctl Tunables
Critical
Warnings
Suggestions
Ok
-------------------------------------------------------------------
ARP Flux
0
0
0
10
RP Filter
0
0
0
5
Network Buffers
0
2
8
0
Scheduler
0
0
1
0
Ethernet Devices
-------------------------------------------------------------------
eth8
0
0
2
1
eth5
0
0
2
1
eth7
0
0
2
1
eth6
0
0
2
1
eth9
0
0
2
1
20
Installing and Configuring HIT/Linux