PFS vs SFS vs FFS - Best Filesystem

[utri007]

Originally Posted by nikosidis

I see some strange advice here. Why are people recommending FFS?

I got my system PFS partition crashed, so that it didn't boot at all. That is something wich hasn't happen to me when FFS is used.

SFS and PSF has their benefits, but FFS hasn't ever let me down.

[klx300r]

Originally Posted by utri007

I got my system PFS partition crashed, so that it didn't boot at all. That is something wich hasn't happen to me when FFS is used.

SFS and PSF has their benefits, but FFS hasn't ever let me down.

FFS never did for me too UNTIL last month with new OS3.1.4 FFS..power went out during copying files to my 25GB partition and it was GONE..bye bye..there is no program that can 'repair' it like DiskSalv did for me over the years as sadly it only works on partitions less than 4GB...the new DiskDoctor only will try to 'recover' whatever 'files' it can...so here I am for first time trusting the same 25GB with PFSaio fingers crossed for the next power 'accident'

[Radertified]

This whole thread seems to be:

Person:
FFS has never failed me

A different person:
PFS has never failed me

Someone completely different:
SFS has never failed me

I wish there was a more definitive answer to which is best these days. Perhaps a poll might help us visualize it better.

[meynaf]

There is no "best" file system, all have their pros and cons. And all can eat data, this is life.

[daxb]

Indeed. Choose the filesystem you like and make backups is a good strategy.

[jasonsbeer]

So, what are the pros and cons to porting a more modern file system, like EXT4 or ZFS, to the Amiga?

[meynaf]

What characteristics must a filesystem have to qualify as "modern", aside of the date it was designed ?

[Thomas Richter]

Originally Posted by jasonsbeer

So, what are the pros and cons to porting a more modern file system, like EXT4 or ZFS, to the Amiga?

The completely different design of the operating system, and the lack of developers wanting to tackle the task to reimplement the file systems.


Under Linux (or Unixoid operating systems in general) the file system is not a process, it is rather a collection of functions that operate in the context of the process using file system functions. Thus, for example, if two processes under *ix want to access the disk, there are "two copies" of the file system operating, and coordination of the access happens inside the file system functions, which then go to the disk I/O layer to get their job done.


Under Amiga, a file system is a process of its own. There is only a single process, and if two programs want to perform disk I/O, they talk to the very same single process. This implies that if you want to get better performance from the file system, the file system must remain reactive and accept commands while disk I/O is busy - this is the "multi-threading ability" of the FFS I talked about.


The AmigaDOS (actually, Tripos) design has its merrits, but also has its drawbacks. It eases the implementation of simple, single-threaded file systems as it avoids resource conflicts by design, but it makes it harder to implement high-performing file systems as the file system need to multi-thread itself.


One way or another: One cannot take *ix code and port it easily to the Amiga. You would have essentially to re-implement any file system, *and* completely re-design its code to fit to the Tripos design of "a single process per partition".



Just porting ext4 code in a simple way gives you probably an ext4 partition structure, but still a slow file system - you then have the file system as bottleneck as the single task every file operation needs to go through. This is something FFS does right, and SFS does wrong.

[klx300r]

Originally Posted by klx300r

FFS never did for me too UNTIL last month with new OS3.1.4 FFS..power went out during copying files to my 25GB partition and it was GONE..bye bye..there is no program that can 'repair' it like DiskSalv did for me over the years as sadly it only works on partitions less than 4GB...the new DiskDoctor only will try to 'recover' whatever 'files' it can...so here I am for first time trusting the same 25GB with PFSaio fingers crossed for the next power 'accident'

so back to this newly created PSFaio partiton...I'm having issues where I copied over the game Worthy to it and it crashes after intial screen but no issues on my FFS partition so run PFSDoctor to check the newly formed partition and I'm getting 15 ' ERROR:corrupt directory block" and one "ERROR:directory anode has illegal; clustersize" and one 'ERROR: 117 reserved blocks not used but allocated" errors from only the 4 folders I created


I'm going to shut down my A4000 for now and if anyone knows why this would happen on new partition let me know



btw I did change the default Max Transfer figure to 0x1FE00 but same issue...

[Thomas Richter]

Originally Posted by klx300r

btw I did change the default Max Transfer figure to 0x1FE00 but same issue...

Before or after the corruption? Once the damage is done, adjusting the mask helps nothing. Set the mask, re-install, then try again - in this order.

[klx300r]

Originally Posted by Thomas Richter

Before or after the corruption? Once the damage is done, adjusting the mask helps nothing. Set the mask, re-install, then try again - in this order.

yes that's what i did Thomas and same issue ?

[klx300r]

..well I tried to get the partition working ok with PFSaio but I guess no luck for me...just put new FFS back and now WORTHY working fine again and no weird errors from freshly partitioned and formatted drive with only few folders from PFSDoctor.....next step is to get a similarly large backup drive for my A4000 so don't have to go through any of this again

update:
some SysInfo results from same partition with FFS and PFSaio below

FFS OP/s / PFSaio
create 61 / 167
open 264 / 803
DirScan 436 / 11340
Delete 2061 / 711
Seek/Read 5187 / 6644
MB/s
CreateFile 2.41 / 2.18
WriteFile 2.50 / 2.22
ReadFile 2.22 / 2.20
RawRead 2.12 / 2.20

[falken]

Is it possible to migrate from FFS to PFS without losing the partitions?

[thomas]

Originally Posted by falken

Is it possible to migrate from FFS to PFS without losing the partitions?

Not directly. but you can migrate from FFS to AFS and then upgrade AFS to PFS.

Don't know about the features of AFS, though. Probably it can't do more than 4GB.

[falken]

Originally Posted by thomas

Not directly. but you can migrate from FFS to AFS and then upgrade AFS to PFS.

Don't know about the features of AFS, though. Probably it can't do more than 4GB.

Is there any risk of losing data in the process?
Where can I read about the process to do the migration?

[alexh]

You'd be mad to try if the data is important and not backed up. Back it up and if the conversion works you've saved yourself time perhaps? If not reinstall from your backup

[meynaf]

I would personnally never attempt to do this kind of operation "in place".
Rather, copy all data to another place (even if it's another partition on the same drive), change the file system of the old partition (this does not affect the others), do quick format on it, then move all data back.

[falken]

Which file system is better, PFS or New FFS (3.1.4)?

[thomas]

The criteria has not changed since the beginning of this thread. PFS is the fastest, FFS has the best data safety. There is not "the better" file system.

[shades_aus]

PFS3 updated by Toni is by far, the fastest AMIGA filesystem out there and has support for larger disks and is still being activly developed, with source code available.
I currently use PFS3AIO on a CF card without issues, daily, both in a real AMIGA and in WinUAE.
I have heard of people with issues using it previously however, a lot has changed since Toni took up development. That said, you absolutely need to read the instructions to implement it properly.
Besides, you are supporting an active AMIGA developer.