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-   -   How is btrfs meant to be used? (https://talk.maemo.org/showthread.php?t=95725)

AapoRantalainen 2015-07-13 20:47

How is btrfs meant to be used?
 
I filled whole /dev/mmcblk0p28 on jolla and rm:ing files is not freeing space. Even rm gives "No space left on device".

How this btrfs is meant to be used? Do I really need to read everything about subvolumes, snapshotting and balancing if I want use it just like ext4?

javispedro 2015-07-13 21:16

Re: How is btrfs meant to be used?
 
If you are on a recent enough Sailfish version, you can try playing with the btrfs-balancer command, e.g. "btrfs-balancer balance" (as root...).

Otherwise, look up the older balancing instructions in jollatogether.

Please note that btrfs is worse than ext4 in almost any benchmark, and I would even say has a more stupid design, save for precisely the features you don't want (subvolumes, snapshotting, CoW). _Specially_ the completely broken version that is shipped on the Jolla kernel. Therefore, maybe you want a ext4 formatted SD card...

AapoRantalainen 2015-07-14 06:55

Re: How is btrfs meant to be used?
 
Needed:
Code:

zypper install btrfs-balancer
Luckily I had space for it.


Code:

btrfs fi show
        devid    1 size 13.75GiB used 13.75GiB path /dev/mmcblk0p28
btrfs-balancer balance
btrfs fi show
        devid    1 size 13.75GiB used 9.82GiB path /dev/mmcblk0p28

-> Great.

But this is not acceptable that I (as an user) needed to do that.

coderus 2015-07-14 08:03

Re: How is btrfs meant to be used?
 
you do not need to do that manually. the only you need is to keep your phone on charger at night, and it will balance automatically when needed.

nieldk 2015-07-14 08:11

Re: How is btrfs meant to be used?
 
Quote:

Originally Posted by coderus (Post 1476578)
you do not need to do that manually. the only you need is to keep your phone on charger at night, and it will balance automatically when needed.

Thats how it 'should' work. Not always perfect though :P
BTRFS was a stupid choice, and gives more troubles than it solves problems.
Unfortunately, it is as hard to ditch as the (in)famous Aegis

juiceme 2015-07-14 08:30

Re: How is btrfs meant to be used?
 
Quote:

Originally Posted by nieldk (Post 1476579)
Thats how it 'should' work. Not always perfect though :P
BTRFS was a stupid choice, and gives more troubles than it solves problems.

Actually BTRFS was a good choise and made sense when it was decided to be used. (and still does) BTRFS has good feature set that is used and needed on the device and is optimized to minimize FLASH wear.

The real problem is users cramming too much data on the device, so the more sensible choise would have been having the device with 64GB storage in the first place... :)

Quote:

Originally Posted by nieldk (Post 1476579)
Unfortunately, it is as hard to ditch as the (in)famous Aegis

Totally different thing, Aegis was meant to be a barrier for users, whereas Jolla choise of FS is a blessing for you :eek:

nieldk 2015-07-14 08:47

Re: How is btrfs meant to be used?
 
Quote:

Originally Posted by juiceme (Post 1476582)
Actually BTRFS was a good choise and made sense when it was decided to be used. (and still does) BTRFS has good feature set that is used and needed on the device and is optimized to minimize FLASH wear.

I dont see how running btrfs balance every night helps ;)
I disagree with you hehe

Quote:

Originally Posted by juiceme (Post 1476582)
The real problem is users cramming too much data on the device, so the more sensible choise would have been having the device with 64GB storage in the first place... :)

Oh yeah! I do that :P
And +1 for more memory


Quote:

Originally Posted by juiceme (Post 1476582)
Totally different thing, Aegis was meant to be a barrier for users, whereas Jolla choise of FS is a blessing for you :eek:

Yes, different thing, same issue. Cant get rid of it easily ;)

coderus 2015-07-14 08:55

Re: How is btrfs meant to be used?
 
imho btrfs is just because of qualcomm architecture

javispedro 2015-07-14 11:04

Re: How is btrfs meant to be used?
 
Quote:

Originally Posted by AapoRantalainen (Post 1476570)
But this is not acceptable that I (as an user) needed to do that.

I fully agree. I mean, I would say adopting btrfs would be a risky move _today_. And Jolla adopted it years ago AND probably knew they would be stuck with their current kernel version. I'd never used btrfs in this situation!

Perhaps they're still planning to use for something more useful than factory restore (e.g. snapshots?). But I keep thinking that the factory restore usecase would best be served with recovery images...

Quote:

Originally Posted by juiceme (Post 1476582)
Actually BTRFS was a good choise and made sense when it was decided to be used. (and still does) BTRFS has good feature set that is used and needed on the device and is optimized to minimize FLASH wear.

Not sure about whether it minimizes flash wear by any measure... The feature set is nice, but is barely used by Sailfish (not a bad thing since that makes SFOS mostly FS independent). To my knowledge only factory restore uses _any_ btrfs feature!

Quote:

Originally Posted by juiceme (Post 1476582)
The real problem is users cramming too much data on the device, so the more sensible choise would have been having the device with 64GB storage in the first place... :)

Yeah well, I'm in the group who thinks that if the filesystem fails to handle ENOSPC (no free space error) properly, it's broken beyond repair. On Ext4, reserving around 5% of blocks/inodes ensures this problem almost never happens. On Btrfs, how many blocks you need to reserve? 83%?

Quote:

Originally Posted by coderus (Post 1476589)
imho btrfs is just because of qualcomm architecture

Doubt it, since all the other qcom partitions are ext4...

nieldk 2015-07-14 11:23

Re: How is btrfs meant to be used?
 
Quote:

Originally Posted by javispedro (Post 1476597)
Doubt it, since all the other qcom partitions are ext4...

Code:

(parted) p
Model: MMC MAG2GC (sd/mmc)
Disk /dev/mmcblk0: 15.6GB
Sector size (logical/physical): 512B/512B
Partition Table: gpt
Disk Flags:

Number  Start  End    Size    File system    Name        Flags
 1      17.4kB  4194kB  4177kB                  emgdload
 2      33.6MB  67.1MB  33.6MB                  QOTP
 3      67.1MB  71.3MB  4194kB                  Qfa
 4      71.3MB  75.5MB  4194kB                  Qcfg
 5      75.5MB  79.7MB  4194kB                  Qdlog
 6      79.7MB  81.8MB  2097kB                  Qvariables
 7      81.8MB  83.9MB  2097kB                  Qlogfilter
 8      101MB  105MB  4194kB                  fsg
 9      134MB  185MB  50.3MB  ext4            Qglog
10      185MB  189MB  4194kB                  modemst1
11      189MB  193MB  4194kB                  modemst2
12      193MB  195MB  2097kB                  sbl1
13      195MB  197MB  2097kB                  sbl2
14      197MB  199MB  2097kB                  sbl3
15      199MB  201MB  2097kB                  tz
16      201MB  203MB  2097kB                  rpm
17      203MB  206MB  2097kB                  aboot
18      206MB  273MB  67.1MB  fat16          modem      msftdata
19      273MB  281MB  8389kB  ext4            drm
20      281MB  294MB  12.6MB                  boot
21      294MB  306MB  12.6MB                  recovery
22      306MB  315MB  8389kB                  pad1
23      315MB  323MB  8389kB                  misc
24      323MB  856MB  533MB  linux-swap(v1)  swap
25      856MB  864MB  8389kB  ext4            persist
26      864MB  864MB  8192B                  ssd
27      864MB  872MB  8389kB                  security
28      872MB  15.6GB  14.8GB  btrfs          sailfish



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