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May 8th, 2015 05:00
Fail over process dell equal logic ps6210 boxes
Hi all,
I have a question regarding those Dell Equal Logic PS6210 Boxes. I have implemented three boxes which are joined in a group and running in auto tearing one of them is SSD and other two are SAS and NLSAS. After that i started creating volumes on those boxes by accessing my SAN Storage using that group IP. And for now everything is working fine.
One day i have to shutdown my infrastructure for maintenance and then i noticed if any of the box goes off first all the volumes created on that box goes offline. By seeing this kind of behavior a question comes to my mind what if one of our box goes down due to any reason it can be power issue or any other reason?? What will happen then ??
I really need your help here.
Thanks
Gohar Sultan
Origin3k
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May 8th, 2015 07:00
If you loose a "box" which holds a slice of a volume the effected volume goes offline until the missing member comes back. Think about a Network RAID0.
Its Equallogic DNA to distribute a volume over members within a pool.
If you dont like that
1. Place only one member in a pool
2. If your members have different RAID level you can specify the RAID Preference for a volume. If possible the volume will be stored on a member with have the right RAID type. But thats not a 100% gurantee!
3. With some commandline magic you can edit the volume distribution and disable it. But than you loose a lot of the EQL benefiz and how it works.
Dell EQL offers 99.999% availability and in 7 years with not 30 members to manage i never loose one.
BTW: placing a hybrid or all SSD member together with a high capacity SATA/NLSAS one together in the same pool it not the "best" setup.
Regards,
Joerg
goharsultan
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May 9th, 2015 08:00
Hi,
Thanks a lot for your response can you please guide me where i can find more details about EQL like if you can suggest some pdf docs on it's process and some on best practices.
And one thing more if we place SSD in different pool then does auto tiering function will work or not. Because our data is bit like we need the most recent data in SSD so that we would have faster I/O process and then after some time that data is transferred to our SAS box and after a month or two that data is transferred to our NLSAS box. What would you suggest in this scenario.
Again thanks a lot for your time.
Regards,
Gohar Sultan