Unless you're in GIMP working on JPEGs, or doing some kind of MPEG
video editing--or ripping audio (MP3 / AAC / FLAC) stuff. All of
which are probably some of the largest files in most people's
homedirs nowadays.
indeed. I think only programmers will see any substantial benefit
from compression, since both the code itself and the object files
generated are easily compressible.
If we are talking about data on people's desktops and laptops, yes, it is
not very common to see a lot of compressible data. There will be some other
examples, such as desktops being used for engineering drawings. The CAD
files do tend to be compressible and they tend to be big.
In any case, the really interesting case for compression is for business
data (databases, e-mail servers, etc.) which tends to be quite compressible.
...
I'd be interested to see benchmarks on MySQL/PostgreSQL performance
with compression enabled. my *guess* would be it isn't beneficial
since they usually do small reads and writes, and there is little gain
in reading 4 KiB instead of 8 KiB.
OK, now you have switched from compressibility of data to performance
advantage. As I said above, this kind of data usually compresses pretty
well.
I agree that for random reads, there wouldn't be any gain from compression.
For random writes, in a copy-on-write file system, there might be gains,
because the blocks may be arranged in sequential fashion anyway. We are in
the process of doing some performance tests to prove or disprove this.
Now, if you are using SSDs for this type of workload, I'm pretty sure that
compression will help writes. The reason is that the flash translation
layer in the SSD has to re-arrange the data and write it page by page. If
there is less data to write, there will be fewer program operations.
Given that write IOPS rating in an SSD is often much less than read IOPS,
using compression to improve that will surely be of great value.
At this point, this is educated guesswork. I'm going to see if I can get my
hands on an SSD to prove this.
Monish
what other uses cases can benefit from compression?
--
Kjetil T. Homme
Redpill Linpro AS - Changing the game
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