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From Alan Bell <alan.b...@theopenlearningcentre.com>
Subject Re: document insert rate
Date Sun, 04 Jan 2009 22:12:37 GMT
Geir Magnusson Jr. wrote:
>
> On Jan 4, 2009, at 2:59 PM, Damien Katz wrote:
>
>> What you say is possible, but doesn't seem too likely as I don't ever 
>> recall any report of a corrupt db on Linux, but before the F_FILESYNC 
>> change in Erlang we would see reports of corruptions on OS X due to 
>> power loss. Since the change, we've had no reports of corrupt 
>> databases on OS X or Linux.
>
> Have you seen the correlation between the # of pirates and global 
> warming? :)
>
> There may be correlation here between the Erlang update and 
> corruption, but I don't see the causality -  fsync() on linux should 
> only get as far as the on-device buffering if it does write buffering, 
> whereas if the OS X docs are truthful, the F_FILESYNC fcntl() pushs 
> the bits to the rust on the platter.  Maybe they fixed something else 
> in that erlang update, or maybe the universe is smiling upon CouchDB 
> users or ....
. . . maybe the ec2 virtual machine instance and abstracted storage 
thingie isn't getting to the rust, even though from the point of view of 
the inside of the VM it thinks it has. I don't know for sure, but a 
comparitive on a real Linux box would be worthwhile. Do you have some 
simple benchmark code to share and I will give it a go on a few Linux 
machines. Would also be interesting to compare SSD to rotating HDD.

Alan.

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