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Linux HIT is disconnecting my Compellent iSCSI connections
I'm trying to connect my Oracle Linux 7.3 system to an EqualLogic (using HIT 1.4 for multipath ) and a Compellent (using standard linux multipath). The issue I have is that the HIT EHCMD daemon is disconnecting half of my Compellent iSCSI connections so I'm losing half of my paths and the Compellent is complaining about it. And to temporary fix the problem I issue a "iscsiadm -m node -l" to re-login to the Compellent and my missing sessions are coming back but after a few minutes the EHCMD will disconnect them again. The error I have in the EHCMD logs are:
|ERROR|IscsiPolling|2443|Forcibly logging out incomplete session 10
|INFO|DoLogout|565|Logging out of session ID 10
Any ideas why the EqualLogic HIT is disturbing my Compellent iSCSI sessions even thought they have nothing to do with each other? How can I tell EHCMD to mind his own business and only manage my EqualLogic and leave my Compellent alone?
dwilliam62
3 Apprentice
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1.5K Posts
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October 20th, 2018 12:00
Hello,
Are you using the same NICs for both EQL and SC? Best option is to split them off completely. Are you running two fault domains on the SC and sharing IP subnet one with EQL?
I would suggest opening a support case for this issue.
Regards,
Don
casfr
11 Posts
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October 21st, 2018 12:00
Same NICs, two fault domains (but within the same subnet) on the SC, same subnet for the EQL and SC but technically this should not be a problem. I am using the same type of setup on my VMware clusters (ESXi 6.5 with HIT 1.5) and I don't have any problem. So it sound like an issue with HIT 1.4 and/or Oracle Linux 7.3 and/or I'm missing some options on the HIT config. I'm seeing a lot of "exclude" features inside the rswcli manual but it's not very clear on what it does and honestly the Linux HIT documentation is not very good.
The idea is to get rid of the EqualLogic and move the files to the Compellent. So if I don't fix this "HIT => iSCSI session logout" issue then we will run with missing SC paths for a few days until the files are completely moved over the SC and then we will get rid of the EQL/HIT and this issue will not be an issue anymore. I will also ask our DBA if upgrading the OS and the HIT could be an option but we are trying to do everything without downtime as most as possible so upgrading might not be an option.
And I could try to open a case with Dell but I guess it would be on the Compellent side because we don't have support anymore for this EQL.
DELL-Bob Mi
230 Posts
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October 21st, 2018 13:00
I was watching the forum and saw your post. I am not trained in EqualLogic, but I am fully trained in Compellent. I am not familiar with the issue you are describing. I will guess you are following this document: Using HIT/Linux and ASM/LE with Dell PS Series Storage
https://downloads.dell.com/solutions/storage-solution-resources/hit-linux_asm-psseries(tr1082)2.pdf
When looking at Best Practices for Sharing an iSCSI SAN Infrastructure with Dell PS Series and Dell SC Series Storage using Linux Hosts
https://downloads.dell.com/solutions/storage-solution-resources/PS-Series-SC-Series-Sharing-Linux-Host-iSCSI-SAN-Dell-2016-(2032-A-BP-INF).pdf
I show that on page 11: PS Series specific host settings without HIT/Linux
Note: For more configuration information pertaining to Dell PS Series and Linux without the HIT/Linux kit, refer to Red Hat Enterprise Linux Configuration Guide for Dell Storage PS Series Arrays
http://downloads.dell.com/solutions/storage-solution-resources/%283199-CD-L%29RHEL-PSseries-Configuration.pdf
It looks like the SC configuration does not use HIT since it only works with the EqualLogic platform. See page 21 of the Best Practices for Sharing:
Configuring the RHEL iSCSI software initiator to access volumes
Use the following steps to query and establish iSCSI sessions from a Linux host to access SC Series volumes. These steps are also used when accessing PS Series volumes without the HIT/Linux kit