GENERAL ERROR: In some environments, PureDisk Remote Office Edition 6.5.x can lose connectivity with Dell Equalogic iscsi based /Storage volume arrays due to iscsid disconnects when under load.

Article:TECH64283  |  Created: 2008-01-21  |  Updated: 2009-01-13  |  Article URL http://www.symantec.com/docs/TECH64283
Article Type
Technical Solution


Environment

Issue



GENERAL ERROR: In some environments, PureDisk Remote Office Edition 6.5.x can lose connectivity with Dell Equalogic iscsi based /Storage volume arrays due to iscsid disconnects when under load.

Solution



The issue:
PureDisk 6.5.x loses connectivity to Dell Equalogic iscsi based /Storage volume arrays due to iscsid disconnects while under load when the array dynamically changes IP addresses.

Troubleshooting:
Dell Equalogic iscsi disk arrays contain a feature that dynamically load balances network traffic by changing IP addresses for iscsi initiator/target traffic. This will cause problems when the default pdiptables rules (within /etc/puredisk/iptables-rules) detect a stateless inbound TCP connection from a new/different Equalogic IP address. Iptables will drop this new, stateless connection. If the iscsid reconnection takes longer than 1 second, the result is a loss of iscsid connectivity between PDOS and the array which can cause a complete loss of access with the array based /Storage volume(s).

When PDOS loses access to the iscsi based /Storage volume(s), /var/log/messages will report iscsid connectivity issues:
Jun 11 01:05:02 hostname kernel: iscsi: host reset succeeded
Jun 11 01:06:15 hostname iscsid: connection0:0 is operational after recovery (1 attempts)
Jun 11 01:06:43 hostname kernel: iscsi: host reset succeeded
Jun 11 01:07:13 hostname iscsid: connection0:0 is operational after recovery (1 attempts)
Jun 11 01:07:40 hostname iscsid: connection0:0 is operational after recovery (1 attempts)
Jun 11 01:09:00 hostname kernel: connection0:0: iscsi: detected conn error (1011)
Jun 11 01:09:00 hostname iscsid: detected iSCSI connection 0:0 error (1011) state (3)
Jun 11 01:09:03 hostname kernel: iscsi: host reset succeeded

Resolution:

Edit file custom_iptables_rules to define the IP address of the additional NIC(s) on the Equalogic iscsi array from source TCP port 3260.

1. Log into each PureDisk node as root.

2. Use a text editor to open the following file: /etc/puredisk/custom_iptables_rules

This file contains a table that you can use to add one or more lines to specify the IP address of the second, and any additional, NIC(s).
For example:
# protocol (tcp,udp,icmp,all) # source[/mask] # port
tcp                    192.168.1.44                        3260
tcp                    192.168.1.45                        3260
 
3. Save and close the file.

4. Run the following command to repopulate PureDisk's firewall information with the new rule:
# sh /opt/pdconfigure/scripts/installers/ChangeIPTables.sh


Legacy ID



311995


Article URL http://www.symantec.com/docs/TECH64283


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