[General] Any linux gurus?

[Arthur]

Is "chattr" really needed for ext2?  I normally just use "noatime" as a
mount option in my fstab.

Side Rant:

While I love btrfs, apparently you can't mount a subvolume as read only
"/", and then mount other subvolumes as read/write for things like "/var".
I've actually found a use case where my choice of filesystem leaves me less
secure :(


On Mon, Dec 16, 2013 at 8:26 PM, Stephan Henning <shenning at gmail.com> wrote:

> -WD
>
> Ya, I'm going to recommend we look into this and see if other options give
> us some improvement
>
>
> -David
>
> The current benchmark run takes about 10 days to fully solve, which is
> about on par with our longest/largest 'production' problem.
>
> The machines are on a UPS, but it is more for power conditioning than
> uptime. With three of these machines in the rack running all out, the
> largest rackmount units are only good for a few minutes. However, the
> program does 'checkpoint' itself at certain intervals, so we will loose
> some data with a power loss, but usually no more than a few hours worth on
> these really long solves.
>
>
> On Mon, Dec 16, 2013 at 6:28 PM, David <ainut at knology.net> wrote:
>
>> I had completely forgotten about the overhead of atime and did not know
>> the practicality of noatime.  Good catch, Charles.
>>
>> So I recommend that you use a filesystem on the ssd's that does not use
>> journaling, and set the ssd drive directories with (as root) :
>>
>> format the SSD's with ext2 (fat32 is not recommended for high speed usage
>> but may not matter with ssd's and only two files);
>>
>> then,
>>
>> [root at machine /root]#*chattr*  -R +A  /dirofSSDtempdata/
>> (after reformat, of course.)
>>
>>
>> Caveat: without journaling, ensure you have a good battery backup APS on
>> the system.  You probably already have that for something that runs for
>> WEEKS!
>>
>> Also, I hope whoever wrote the program made it re=entrant with little
>> loss of time in case the system did crash, for whatever reason.
>>
>>
>> David M.
>>
>>
>>
>> Charles Moye wrote:
>>
>>> and set noatime?
>>>
>>>
>>>
>>> On Mon, Dec 16, 2013 at 9:45 AM, David <ainut at knology.net <mailto:
>>> ainut at knology.net>> wrote:
>>>
>>>     Can't remember if ext4 uses journaling but if it does, you'll get
>>>     better times if you can turn it off.
>>>
>>>
>>>
>>>     Stephan Henning wrote:
>>>
>>>>     Wow, nice.
>>>>
>>>>     -WD, I've gone in and checked, and at least on the SSD array,
>>>>     it's ext4.
>>>>
>>>>
>>>>     On Mon, Dec 16, 2013 at 7:01 AM, Matt <brimstone at the.narro.ws
>>>>     <mailto:brimstone at the.narro.ws>> wrote:
>>>>
>>>>         On 12/15/2013 10:37 PM, Arthur wrote:
>>>>         > What did mailman do?
>>>>
>>>>         Arthur,
>>>>
>>>>         Mailman's default setting for digests is to send them out
>>>>         every 30KB.
>>>>         People don't trim messages like the bad old days; Ethan's
>>>>         response email
>>>>         after yours is 35KB alone. I upped the setting to 10MB, which
>>>>         is Gmail's
>>>>         inbound limit if I recall correctly.
>>>>
>>>>         #matt
>>>>
>>>>
>>>>
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>>>>
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-- 
Sincerely,
Arthur Moore
(256) 277-1001
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