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Marcus Holland-Moritz 2020-11-25 13:27:10 +01:00
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@ -16,11 +16,11 @@ this redundancy. See [here](#comparison) for a comparison with other
compressed file systems.
DwarFS also **doesn't compromise on speed** and for my use cases I've
found it to be on par with or perform better than SquashFS. **For my
primary use case, DwarFS compression is an order of magnitude better
than SquashFS compression, it's 4 times faster to build the file
system, it's typically faster to access files on DwarFS and it uses
less CPU resources.**
found it to be on par with or perform better than SquashFS. For my
primary use case, **DwarFS compression is an order of magnitude better
than SquashFS compression**, it's **4 times faster to build the file
system**, it's typically faster to access files on DwarFS and it uses
less CPU resources.
Distinct features of DwarFS are:
@ -235,14 +235,14 @@ These tests were done on an Intel(R) Xeon(R) CPU D-1528 @ 1.90GHz
6 core CPU with 64 GiB of RAM. The system was mostly idle during
all of the tests.
The source directory contained 1139 different Perl installations from
284 distinct releases, a total of 47.65 GiB of data in 1927501 files
and 330733 directories. The source directory was freshly unpacked
from a tar archive to a 850 EVO 1TB SSD, so most of its contents
were likely cached.
The source directory contained **1139 different Perl installations**
from 284 distinct releases, a total of 47.65 GiB of data in 1,927,501
files and 330,733 directories. The source directory was freshly
unpacked from a tar archive to a 850 EVO 1TB SSD, so most of its
contents were likely cached.
I'm using the same compression type and level with SquashFS that is
the default setting for DwarFS:
I'm using the same compression type and compression level for
SquashFS that is the default setting for DwarFS:
$ time mksquashfs install perl-install.squashfs -comp zstd -Xcompression-level 22
Parallel mksquashfs: Using 12 processors
@ -315,15 +315,15 @@ For DwarFS, I'm sticking to the defaults:
sys 3m9.115s
So in this comparison, `mkdwarfs` is more than 4 times faster than `mksquashfs`.
In total CPU time, it's actually 7 times faster.
In total CPU time, it's actually 7 times less CPU resources.
$ ls -l perl-install.*fs
-rw-r--r-- 1 mhx users 555118147 Nov 24 23:27 perl-install.dwarfs
-rw-r--r-- 1 mhx users 4748902400 Nov 25 00:37 perl-install.squashfs
In terms of compression ratio, the DwarFS file system is more than 8 times
smaller than the SquashFS file system. With DwarFS, the content has been
compressed down to 1.1% (!) of its original size.
In terms of compression ratio, the **DwarFS file system is more than 8 times
smaller than the SquashFS file system**. With DwarFS, the content has been
**compressed down to 1.1% (!) of its original size**.
DwarFS also features an option to recompress an existing file system with
a different compression algorithm. This can be useful as it allows relatively
@ -451,9 +451,11 @@ shown above for DwarFS obviously don't include the time spent in the
sys 0m2.117s
So in total, DwarFS was using 10.5 seconds of CPU time, whereas
SquashFS was using 23.5 seconds, more than twice as much.
SquashFS was using 23.5 seconds, more than twice as much. Ignore
the 'real' time, this is only how long it took me to unmount the
file system again after mounting it.
Another real-life test was to build and test a Perl module with 468
Another real-life test was to build and test a Perl module with 624
different Perl versions in the compressed file system. The module I've
used, [Tie::Hash::Indexed](https://github.com/mhx/Tie-Hash-Indexed),
has an XS component that requires a C compiler to build. So this really
@ -490,7 +492,8 @@ releases between 5.10.0 and 5.33.3, a total of 624 `perl` installations:
$ time ls -1 /tmp/perl/install/*/perl-5.??.?/bin/perl5* | sort -t / -k 8 | xargs -d $'\n' -P 8 -n 1 ./build.sh
Tests were done with a cleanly mounted file system to make sure the caches
were empty. With SquashFS, the timing was:
were empty. `ccache` was primed to make sure all compiler runs could be
satisfied from the cache. With SquashFS, the timing was:
real 3m17.182s
user 20m54.064s