[DRBD-user] configuring 2 services on 2 hosts

J j at koarcg.com
Thu Jan 6 16:46:40 CET 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


On 1/6/2011 8:09 AM, Timo Schoeler wrote:
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> thus Digimer spake:
>> On 01/06/2011 03:27 AM, Felix Frank wrote:
>>>> In any case, be sure to have (at least) RAID 1 on each node backing the
>>>> DRBD devices to help minimize downtime. Drives fail fairly frequently...
>>>> software RAID 1 is an inexpensive route to much better uptime. :)
>>> If the budget isn't severely restricted, I'd also throw in an actual
>>> RAID controller, software RAID being an unnecessary pain.
>>>
>>> Cheers,
>>> Felix
>> If I may provide a counter-point arguing in favour of software RAID;
>>
>> With hardware RAID, you array and your data is bound to that controller.
>> Should the controller fail at some point, you will find yourself
>> scrambling trying to find a compatible controller, and you will be down
>> until you do (shy of falling back to recovering from backup). I had this
>> happen to me enough that I now won't use hardware RAID unless it's for
>> performance (or similar) reasons the make software RAID unfeasible.
>>
>> With software RAID, you have a familiar set of tools (mdadm) that many
>> people can help you with. More importantly though, you can move your
>> array to almost any other machine and get it up and running again with
>> relatively little effort, potentially dramatically reducing your mean
>> time to recovery.
> I may add that in most cases management as well as performance
> monitoring of a software will run like a charm compared to most
> solutions and tools vendors offer - regardless of what OS you use.
>
>> Cheers!
>

Thanks for the suggestions. I've been using linux software raid for 
years, and I've been very pleased with the results. Never lost a bit 
actually :) After doing some research, I've decided to hold off on the 
SSD drives until I get the system up in a state that can be tested with 
the platter-based hard drives. After doing a lot of reading (like 
anandtech.com), I'm worried about the long-term stability of SSD 
devices. Also, the price differences between the "consumer-grade 
crapware" and "enterprise-level sweetness" is pretty big. I was looking 
at getting some ocz vertex 2's, but stability concerns really scared me. 
I don't think x25's are in my budget (for the size I want).

I'm going to set it up first with platter-based HDD's (4 total, each 
host with raid1). Have 1 MD device (PV) running under lvm with 3 lv's. 
One for system partition, one for app1 that will be under drdb and one 
for postgresql and mysql that will be under drdb.

If needed, I'll throw in 4 more disks, make another vg and migrate 
postgresql/mysql data to that.

Again, Thanks for all your recommendations!
J





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