The small linux problem thread

Operating Systems & Open Source Linux
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2324

Lvm does snapshots

1 Like
2325

cool, so does BTRFS

1 Like
2326

not trolling, really, but does btrfs still mangle raid5?

2327

yes, dont use 5/6 on BTRFS

3 Likes
2328

https://btrfs.wiki.kernel.org/index.php/RAID56

So some work has been done but still unsafe for metadata. You can MDADM a raid5 and then just put BTRFS on the partition.

#Edit: Don’t think Raid 5 is too high on the list of things to do - no one should be using this with high capacity drives anyway.

2 Likes
2329

or you can run raid5/6 for data and raid 1 for metadata

2 Likes
2330

This is probably the simplest solution.

2331

or just use zfs

2 Likes
2332

I really like ZFS - just not for my desktop. I run it only on servers - don’t like how it uses RAM on a workstations - prefer BTRFS on there.

1 Like
2333

yes, if you’re not booting off of the RAID, and you’re not running a distro that gets fast kernel updates.
and:

2334

There are some parameters to limit ram use, but they only work properly on FreeBSD, and Linux just sometimes ignores them.
screenpunch

2335

From my experience with ZFS on linux, the arc cache won’t evict for other programs either. The only way to evict it is to clear it entirely.

2336

Anyone know if an environment variable or a file is created/touched when a reboot is scheduled?

(i.g. shutdown -r +20 )

2337

So… What’s the difference between su and su - ?

Commands under root work under su - but not su :thinking:

2338

Alias?

2339

The man page is your friend, su starts an interactive shell whereassu - starts a login shell and setup environment variables etc for the user.

       -, -l, --login
              Start the shell as a login shell with an environment similar to a real login:

                 o      clears all the environment variables except TERM and variables specified by --whitelist-environ‐
                        ment

                 o      initializes the environment variables HOME, SHELL, USER, LOGNAME, and PATH

                 o      changes to the target user's home directory

                 o      sets argv[0] of the shell to '-' in order to make the shell a login shell
4 Likes
2340

This day didn’t go to waste, learned something new

4 Likes
2341

Holy shit. Thanks man!

Btw ur a man page :wink:

x1,000

3 Likes
2342

User env

1 Like
2343

Rtfm instead of google, I bet we all do that mistake too often lol.

To quote Joe McCray, who does pentesting and used to use an ascii chart as a mousepad as memo:
“One night when I was UNBELIEVABLY drunk, I had this idea to type ‘man ascii’ and all that shit was right there!
I was like DAYUUUM…”

One of my idols. Does great work, smart guy:

5 Likes