Btrfs

[kubicle]

I have 6GB of RAM and when I was running Kubuntu with Btrfs I created a 12 GB swap partition specifically for hibernation, in case I wanted to use it (but never have). I noticed on systemguard that the swap was never used, so I deliberately loaded many programs and started as many processes (DL, searches, etc) to use all of my eight cores so I could see what it would take to force the system to use swap. I never could get swap into action. When I went to Neon I didn't install a swap partition and no matter what program or process I use I never experience a slowdown or stall, with one exception. Kdeconnectd would often create a minor delay but I never use it so I disabled it and those delay's ceased.

Most people will probably not need swap on modern machines with plenty of ram (regardless of the file system they use), except for hibernation, and are unlikely to ran out of ram unless there is a bad memory leak or they do some really memory intensive tasks.

It's not uncommon to have no swap used (in fact, if your system uses swap a lot you probably need to install more ram...swap is to be considered "emergency" memory rather than "extended" memory, just that you don't lose unsaved work if you ran out of ram)...although this depends on the system's "eagerness" to swap (the configured vm.swappiness value [sysctl vm.swappiness]).

I'm not taking a stand on whether one should have swap space or not, just wanted to mention that you could even if you use btrfs.

[GreyGeek]

I have 6GB of RAM and when I was running Kubuntu with Btrfs I created a 12 GB swap partition specifically for hibernation, in case I wanted to use it (but never have). I noticed on systemguard that the swap was never used, so I deliberately loaded many programs and started as many processes (DL, searches, etc) to use all of my eight cores so I could see what it would take to force the system to use swap. I never could get swap into action. When I went to Neon I didn't install a swap partition and no matter what program or process I use I never experience a slowdown or stall, with one exception. Kdeconnectd would often create a minor delay but I never use it so I disabled it and those delay's ceased.

[kubicle]

1: It doesn't need or use swap, so don't waste your space, that also means no suspend or hibernate

Technically, no file system "needs or uses" swap.

Swap (either swap files or swap partitions) are something the kernel uses as a sort of (slow) extension of ram memory (that resides on disk), not really related to file systems.

Last I checked, btrfs didn't support swap files (swap storage inside a file system), and you can't use swap partitions on a partitionless btrfs disk (using subvolumes)...but you can still use swap partitions with separate btrfs partitions if you wish (if you want hibernation, for example).

[oshunluvr]

jglen490, I'm busy working this week but later this evening I should have some time to post a couple comments and advice. Check back around 6pm.

[GreyGeek]

I am running a 5 year old 17" Acer Aspire V3-771G with 6GB RAM and an Intel HDGraphics as the primary GPU and an NVidia GT650M as the secondary GPU, which cannot be set in the BIOS as the primary GPU. However, the nvidia-781 nvidia-378 driver configures the GT650M as if it were the primary and my plasma desktop and everything it runs uses the nvidia GT650M. Running Minecraft 1.13 with Forge and Optifine I get up to 500 fps. Universe Sandbox^2 runs all simulations smoothly.

I am using a Hurricane IPv6 tunnel with Google's IPv6 DNS to give me a 20/20 at ipv6-test.com.

I'm running KDE Neon User Edition, fully updated, with btrfs on two 750Gb HD's configured in RAID1, with a third 750Gb HD using btrfs as a backup drive.

[FONT=monospace][COLOR=#000000]$ [B]sudo btrfs filesystem df /[/B][/COLOR]
Data, RAID1: total=102.00GiB, used=98.86GiB
System, RAID1: total=32.00MiB, used=16.00KiB
Metadata, RAID1: total=2.00GiB, used=1.09GiB
GlobalReserve, single: total=181.88MiB, used=0.00B

[COLOR=#000000]$ [B]sudo btrfs filesystem show /[/B][/COLOR]
Label: none  uuid: 12980ae8-4117-4cc5-bbb8-8065e82af93d
        Total devices 2 FS bytes used 99.95GiB
        devid    1 size 691.19GiB used 104.03GiB path /dev/sda1
        devid    2 size 698.64GiB used 104.03GiB path /dev/sdc

[COLOR=#000000]$ [B]sudo btrfs filesystem show /dev/sdb1[/B][/COLOR]
Label: none  uuid: 17f4fe91-5cbc-46f6-9577-10aa173ac5f6
        Total devices 1 FS bytes used 265.65GiB
        devid    1 size 698.63GiB used 270.02GiB path /dev/sdb1

[/FONT]

I mount the sdb1 HD only as storage, using btrfs send & receive dated ro snapshots of @ and @home. Then I umount it.

I've been using Btrfs for over 2 years and haven't had a single problem with it, nor have i had to do a roll back. However, I have browsed into snapshots on occasion to fetch config files or previous versions of libraries or programs.

As a retired programmer, among other things, my system holds copies of every major program I've ever written for myself or clients since 1978, plus copies of all my email since around 2000. I'm using 99Gb of HD space.

The only caveats about using Btrfs are:
1: It doesn't need or use swap, so don't waste your space, that also means no suspend or hibernate
2: It uses Copy On Write (COW) so a dynamic virtual HD in VirtualBox is out of the question. Make your virtual HDs static or the directory in which you will save them as NOCOW. I chose static virtual HDs and never had any problem.

I've found that it is easier to create snapshots manually, and takes less space, than to use a tool like Snapper. There are excellent posts describing how to use Btrfs in this forum.

If you do decide to use Btrfs I suggest that your do a fresh install using Btrfs and give your entire drive, /dev/sda1 to it, making sda your boot flag. Also, don't bother with the root & boot partitions or dividing /home into several partitions. With Btrfs that is unnecessary. Btrfs on Ubuntu will create two major subvolumes: @ and @home. (/ and /home) You can create others if you want but that just adds to the complexity. SUSE, for example, makes a subvolume out of just about every major directory in the Linux file system hierarchy.

You can format your 80Gb drive independently with Btrfs without adding it to the pool. Then you can mount it and use it to store backup snapshots. You can also create ASCII copies of snapshots and use it as the destination for those copies. Plus, much, much more .... I haven't even scratched the surface of the power and flexibility of Btrfs

[#]BTRFS[/#]

[vinnywright]

Well I may not be the best one to try to explain it all ,,,,,,,@oshunluvr is our resident expert on btrfs.

but I do use it ,,,,, you do not NEED any special hardware and "btrfs-tools" would be the only package you may not have that you would need ... other than that the file system support is built in.

the btrfs file system can be made in a partition or you can make it on the bare disk with no partitioning necessary. in btrfs land you can have sub volumes on the file system that can contain OS installs (or backups) , so on one btrfs file system you could have several OS's and their is no need to set a set size for the sub volumes as all will expand to use all available space as needed

@hear I am setup like this

vinny@vinny-Bonobo-Extreme:~$ sudo parted -l
[sudo] password for vinny: 
Model: ATA HGST HTS725050A7 (scsi)
Disk /dev/sda: 500GB
Sector size (logical/physical): 512B/4096B
Partition Table: msdos
Disk Flags: 

Number  Start   End    Size    Type      File system     Flags
1      8225kB  323GB  323GB   primary   btrfs           boot
3      323GB   379GB  56.3GB  primary   ext4
4      379GB   496GB  117GB   extended
6      379GB   436GB  57.0GB  logical   ext4
5      436GB   496GB  59.8GB  logical   ext4
2      496GB   500GB  4295MB  primary   linux-swap(v1)

Model: ATA HGST HTS721010A9 (scsi)
Disk /dev/sdb: 1000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags: 

Number  Start   End     Size    File system  Name     Flags
1      1049kB  1000GB  1000GB  btrfs        primary

sda1 is btrfs and has 2 OS installs in it (Neon-LTS and Kubuntu-17.04)

sda3 ext4 Kubuntu-14.04

sda5 ext4 Debian-8-KDE

sda6 ext4 Kubuntu-16.04 with Neon/dev/stable added to the sources.list

sdb1 btrfs is my data drive and is linked to all my installs

sdb1 was an ext4 file system and had my data on it when I did an ,in place, conversion to btrfs ,,,,,,,the data was intact .

the sda1 looks like this

vinny@vinny-Bonobo-Extreme:/media/vinny/ff5d66d4-35b6-4c9c-a64e-8dfbe2aa1e31$ ls
@  @17.04  @17.04snap  @home  @home17.04  @home17.04snap  ubiquity-apt-clone  var

(I'm in the 16.04 , and mounted the partition with dolphin so thats why the /media/vinny/XXXXXXX)

the @ and @home are the Neon-LTS sub volumes ,,,,the @17.04snap and @home17.04snap are "snapshots" (backups) of the 17.04 install I took just before doing something that may have broken the system ,,,,,,,had things gone south all I would have had to do was delete the subvolumes and rename the snaps (remove the "snap" ) and all would have been back to where I started .

btrfs allso has it's own capabilities ,,,,,, but I know little about that ,,,, @oshunluvr dose however , and will chime in on this one soon I'm sure ...

O ,,,is their any reason your using a 32bit install ?

VINNY

[jglen490]

So I've been following the various BTRFS discussions that seem to be everywhere and a part of a lot of different threads. I'm not convinced that I need BTRFS, but I probably could be convinced to want BTRFS. I need to understand what hardware and software that is needed to make this move.

Right now John-Desktop has two mechanical hard drives - 80 GB and 250 GB - each using ext4. These are setup as follows:

John@John-Desktop:~$ df -h
Filesystem      Size  Used Avail Use% Mounted on
udev            4.0G     0  4.0G   0% /dev
tmpfs           804M  9.4M  795M   2% /run
/dev/sda1        12G  6.8G  4.5G  61% /
tmpfs           4.0G  876K  4.0G   1% /dev/shm
tmpfs           5.0M  4.0K  5.0M   1% /run/lock
tmpfs           4.0G     0  4.0G   0% /sys/fs/cgroup
/dev/sda2        59G   24G   33G  43% /home
/dev/sdb1       230G   26G  192G  12% /home/multimedia
tmpfs           804M     0  804M   0% /run/user/118
tmpfs           804M   28K  804M   1% /run/user/1000

John-Desktop also uses two external mechanical hard drives, in enclosures, connected via USB on a rotating basis to take backups using rsync.

The 250 GB drive has enough room to accommodate the data on both internal drives. So I'm guessing that if I were to put everything on the existing 250 GB using BTRFS, I would need at least one more 250 GB drive. But that's just a guess.

I'm guessing that under BTRFS, I could do away with the external backups and somehow configure BTRFS to accommodate recovery requirements. But that too is just a guess.

Help me to understand this process. Thank you!