Open Stack

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On Sun, 7/28/13, Tia Song <song_tia at yahoo.com> wrote:

 Subject: [Openstack-operators] Shared storage HA question
 To: openstack-operators at lists.openstack.org
 Date: Sunday, July 28, 2013, 10:04 AM
 
 >> I have issue with creating
 shared storage for Openstack. Main idea is to 
 >> create 100% redundant shared storage from two
 servers (kind of network 
 >> RAID from two servers).
 >> I have two identical servers with many disks
 inside. What solution can 
 >> any one provide for such schema? I need shared
 storage for running VMs 
 >> (so live migration can work) and also for
 cinder-volumes.
 
 >> One solution is to install Linux on both servers
 and use DRBD + OCFS2, 
 >> any comments on this?
 >> Also I heard about Quadstor software and it can
 create network RAID and 
 >> present it via iSCSI.
 
>> My two cents worth from a generic concept point view of a
 network mirror
 
>> Key factors to evaluate
>> 1. Write latency
>> 2. Active-active or use active-passive with automatic ip
 address failover (using CARP etc)
>> 3. Split brain handling
>> 4. How soon after a node failure are the two node brought in
 sync.
 
>> quadstor shines in many aspects and  DRBD + SCST is a
>> good alternative. You should evaluate both in my opinion.

Forgot one major aspect. Fencing.
1. How easy it is to setup fencing ?
2. Reliability. Definitely hardware fencing ILO, IPMI etc
3. Test, test, test. Simulate heavy IO, bring down the network between the two nodes etc.

-Tia

 

 
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