compressing intermediate files with LZO on the fly

compressing intermediate files with LZO on the fly

[Al Boldi]

Willy Tarreau wrote:
>
> ... for some usages (temporary space),
> light compression can increase speed. For instance, when processing logs,
> I get better speed by compressing intermediate files with LZO on the fly.

How can you do that on ext3?

Also, can you do that on a partition block-io level?


Thanks!

--
Al

Re: compressing intermediate files with LZO on the fly

[Willy Tarreau]

Hi Al,

On Sat, Apr 07, 2007 at 02:32:34PM +0300, Al Boldi wrote:
> Willy Tarreau wrote:
> >
> > ... for some usages (temporary space),
> > light compression can increase speed. For instance, when processing logs,
> > I get better speed by compressing intermediate files with LZO on the fly.
> 
> How can you do that on ext3?
> 
> Also, can you do that on a partition block-io level?

No, sorry for the confusion. My scripts simply do :

 $ lzop -cd file1.lzo | process | lzop -c3 > file2.lzo

With decent CPU, you can reach higher read/write data rates than what a
single off-the-shelf disk can achieve. For this reason, I think that
reiser4 would be worth trying for this particular usage. And in this case,
I'm not interested at all in reliability. It's just temporary storage. If
the disk fails, I throw it away and buy a new one.

Cheers,
Willy

Re: compressing intermediate files with LZO on the fly

[David Lang]

On Sat, 7 Apr 2007, Willy Tarreau wrote:

> Hi Al,
>
> On Sat, Apr 07, 2007 at 02:32:34PM +0300, Al Boldi wrote:
>> Willy Tarreau wrote:
>>>
>>> ... for some usages (temporary space),
>>> light compression can increase speed. For instance, when processing logs,
>>> I get better speed by compressing intermediate files with LZO on the fly.
>>
>> How can you do that on ext3?
>>
>> Also, can you do that on a partition block-io level?
>
> No, sorry for the confusion. My scripts simply do :
>
> $ lzop -cd file1.lzo | process | lzop -c3 > file2.lzo
>
> With decent CPU, you can reach higher read/write data rates than what a
> single off-the-shelf disk can achieve. For this reason, I think that
> reiser4 would be worth trying for this particular usage. And in this case,
> I'm not interested at all in reliability. It's just temporary storage. If
> the disk fails, I throw it away and buy a new one.

I see the same thing with my nightly scripts that do syslog analysis, last year 
I trimmed 2 hours from the nightly run by processing compressed files instead of 
uncompressed ones (after I did this I configured it to compress the files as 
they are rolled, but rolling every 5 min the compression takes <20 seconds, so 
the compression is < 30 min)

now I just need to find a version of split that can compress it's output files.

David Lang