[CentOS] Poor RAID performance new Xeon server?

Sun Jan 11 21:03:37 UTC 2009
Rob Kampen <rkampen at kampensonline.com>


Stewart Williams wrote:
> John R Pierce wrote:
>   
>> Stewart Williams wrote:
>>     
>>> John R Pierce wrote:
>>>   
>>>       
>>>> Stewart Williams wrote:
>>>>     
>>>>         
>>>>> The block I/O is the thing that concerns me as mostly I am serving a 
>>>>> 650MB file via samba to 5 clients and I think this is where I need the 
>>>>> speed.
>>>>>       
>>>>>           
>>>> is this a sequential or random access application thats using this 
>>>> file?   is it read only/mostly, or is it random update?
>>>>     
>>>>         
>>> I'm not sure, how can I find this out?
>>>   
>>>       
>> well, what is the nature of the application thats using this file?     
>> do you really mean just a single 650MB (sub 1GB) file?
>> is this something like a quickbooks file? (thats kind of what it sounds 
>> like from your other answers).
>>     
>
> It is indeed a quickbooks file. The file is currently at 645MB and grows 
> about 20MB per week.
>
>   
>> given what you have now, and what information we've been given, I would
>>
>>     A) disable BIOS raid, configuring it for JBOD w/ ACHI enabled
>>     B) mdadm mirror disks 0 and 1, and put the OS on that
>>     C) mdadm mirror disks 2 and 3, and put your shared SMB filesystem on 
>> that
>>     
>
> Is that a better choice than RAID 1+0?
>
>
>
>
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>   
Hi, I too run quickbooks (2007) and offer the following scenario - 5 
user licences (actually 2 times three user package were purchased).
Previously I used version 2004 and this allows much better sharing of 
the data file, unfortunately I got sucked into an upgrade that in 
reality was a significant downgrade!! Anyway - my set-up:-/
For multiple simultaneous users, one machine has to be the defacto 
"server", i.e. it opens the file and shares access to the underlying 
data store on behalf of other users. (why they can't develop a decent 
client server product defies understanding).
So what I have done is establish a W2K client running in virtualbox 
(thanks to Sun for keeping this product FOSS). This client accesses the 
data file from my main server (running a HW based raid 5  disk array). I 
have lots of ram on my virtual box client, and allocate sufficient to 
ensure all is in ram. Thus far the system has been very robust and no 
data loss. I keep this client running in share mode 24x7 and only go 
single user to create backups. Unfortunately Quickbooks does not provide 
an automated method of backing up (another gross over-sight).

All the other users (on Windoze XP at this time) access the virtualbox 
W2K for the data file.
Performance while not stellar is adequate, my file is only 10% the size 
of yours, but it runs basically from ram, and only save writes....
Apparently Quickbooks do offer more expensive products that may work 
better from a client server perspective but only on Windoze and MAC, but 
for my small business the cost is WAY TOO HIGH and I love FOSS and Linux.

I must say, it took me many dozens of hours to get this working properly 
(mostly due to my ignorance, and Quickbooks poor design), so I hope this 
may assist you.
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