/dev/chat

Faheem Mitha

10:13 AM

How serious is this warning (from my external USB drive, currently being used for backups).

> Device: /dev/sdg [SAT], 1 Currently unreadable (pending) sectors

Should I purchase a new USB drive?

Kusalananda

11:42 AM

Sigh. Neither this nor the second duplicate are duplicates of the "Why is Kali so hard" question: unix.stackexchange.com/questions/508276/…

I've also looked at user's reviews of other questions, and it appears that some users seems to just click a single button in the reviews, for example "Leave Open".

It would be good to have sanity check questions in the review queues, as is done on StackOverflow.

Faheem Mitha

12:33 PM

@Kusalananda Yes, this is ridiculous.

He doesn't have enough space in his root partition, by the looks of it.

I cast the last reopen vote, so it's open now.

Kusalananda

@FaheemMitha Good. It's a pity I can't answer it (never done that on Linux myself).

Faheem Mitha

12:54 PM

@Kusalananda You could just say that there is not enough space.

Kusalananda

@FaheemMitha Well, my comment on the question amounts to that, more or less.

Faheem Mitha

@Kusalananda Sure, I just meant someone could write an answer along those lines.

Kusalananda

@FaheemMitha Q: "I don't have enough space" A: "You don't have enough space"

Faheem Mitha

@Kusalananda Fair enough, but someone could point out where he doesn't have enough space. I guess I could write an answer, but it wouldn't be much of one.

Jeff Schaller

I'm kind of curious what he's done to use up 11 Gb!

(he/she)

Faheem Mitha

1:09 PM

I see Rui voted to quote as a dupe of the infamous "why won't people help me" question. I wonder what he was thinking.

Jeff Schaller

I think a lot of people see the kali tag and short-cut their voting on poorly-asked questions.

Faheem Mitha

Fine, I'm answering it.

@JeffSchaller We just had a discussion about that. I thought Michael covered it pretty well.

If my answer if off-target, please let me know. But I don't think there is much going on here.

Jeff Schaller

@FaheemMitha well, we've had several, with Gilles' followed by karel's, with terdon's response:

> So, I have reopened the question and would like to take this opportunity to ask the community not to automatically close in favor of the "Kali is hard" question. We should only use that as a dupe target when the issue is obviously that the OP is new to Linux and really shouldn't be using Kali because they are new to Linux.

Faheem Mitha

@JeffSchaller Apparently Rui didn't get the memo.

Wow, that was a fast accept.

Jeff Schaller

well, people are free to vote their conscience; it's obvious (to me) that there's some amount of disagreement or confusion about what to do with these questions

just off the top of my head, I think I'd prefer (in general, for the poorly asked happens-to-use-Kali questions), to VTC unclear -- as normal for every other question on the site -- with a link to the Gilles answer

2

(as I said)

Faheem Mitha

1:19 PM

@JeffSchaller That question was anything but unclear.

Granted, the answer was very simple. But we all have to start somewhere. And maybe he was confused.

Jeff Schaller

@FaheemMitha well, certainly that'd be a worse variation of what I'm concerned about; if the question's not even unclear, we should answer it

Faheem Mitha

@JeffSchaller Of course. Well, someone should.

Jeff Schaller

(as opposed to closing it as unclear or a duplicate)

Faheem Mitha

Agreed.

MikiBelavista

2:55 PM

Hi. I have problem,when I run this from Kali terminal

root@kali:~# /dev/mapper/kali--vg-root +10G /dev/mapper/kali--vg-root
bash: /dev/mapper/kali--vg-root: Permission denied

Faheem Mitha

@MikiBelavista What you wrote is not a command. What are you trying to do?

MikiBelavista

Wait please!

Jesse_b

Based on the permission denied error it seems like that file does exist but you just don't have the proper access

doh nvm you are root so yeah it's probably not a regular file or something

Fabby

@Jesse_b >:-)

@MikiBelavista No waiting: What are you trying to accomplish?

MikiBelavista

root@kali:~# lvextend -L +12G /dev/mapper/kali--vg-root
Insufficient free space: 3072 extents needed, but only 5 available

I am trying to extend 12G,as it was suggested.

Fabby

3:01 PM

@MikiBelavista You don't have enough space: buy an additional HDD/SSD

MikiBelavista

No,that is not true.

I am running this command from Kali Linux is that ok?

Fabby

@MikiBelavista Oh, OK. What's the link to your question on-site that gives more information?

Jesse_b

@MikiBelavista (╯°□°)╯︵ ┻━┻

ilkkachu

well, at least the volume group is full, that's what it's trying to say.

MikiBelavista

2

A: Can not upgrade Kali,not enough space in /var/cache/apt/archives

Backup the virual machine ( clone it) then resize the virtual hard drive: To incrase the kali.vdi from ~10 G to ~20 G use the following command (from Ubuntu): VBoxManage modifyhd /Path/to/kali.vdi --resize 20000 Then download Gparted or use a linux live USB. From Virtualbox, navigate to Sett...

ilkkachu

3:03 PM

It might not be backed by the whole disk, but I don't know if that's often useful..

Fabby

@MikiBelavista Ah, Virtual machine: yup: extend the virtual disk then trry again.

MikiBelavista

Fabby,ok,I will

ilkkachu

extend the virtual disk, then the partition, then the LVM physical volume...

Faheem Mitha

Could anyone comment on my USB drive error message? I'll probably buy another one soon, but (a) I kind of hate shopping (b) have other things to do.

Fabby

@MikiBelavista ----^

@FaheemMitha link?

Faheem Mitha

3:11 PM

@Jesse_b He's trying to execute a logical volume. That's unlikely to succeed.

5 hours ago, by Faheem Mitha

> Device: /dev/sdg [SAT], 1 Currently unreadable (pending) sectors

@MikiBelavista You're trying to increase it by 12G, I think. You don't need to increase it by that much.

Fabby

@FaheemMitha what's the output of smartctl --all /dev/sdg ?

Faheem Mitha

@MikiBelavista Output of vgs, please. As root.

@Fabby gist.github.com/fmitha/3b4f25ee83ba8a50b69271b3818e0478

This drive was purchased July 2014, so it's getting a bit long in the tooth.

Fabby

@FaheemMitha But it's still in good health.

@FaheemMitha 197 Current_Pending_Sector 0x0032 200 200 000 Old_age Always - 1

Faheem Mitha

@Fabby I checked around online, and the consensus was that is was probably a sign of bad blocks. And thus not a good sign.

Fabby

Have your tried fully shutting down the machine it's connected to?

Faheem Mitha

3:20 PM

@Fabby What does that mean?

@Fabby No. You mean my workstation?

Fabby

@FaheemMitha It's a hardware error indeed.

@FaheemMitha Yup.

shut down. Not reboot.

Faheem Mitha

@Fabby The computer? Just to be clear, we're talking about an external USB drive.

Fabby

Then the drive should be able to mark that block as a bad block and swap it out.

@FaheemMitha Yup.

Faheem Mitha

What purpose would shutting down the computer serve?

Fabby

@FaheemMitha The block might be in use for something that is not critical.

Faheem Mitha

3:22 PM

@Fabby I don't follow. Why would I need to shut down the computer to do that?

@Fabby I see. That's kind of a pain, but I'll try to remember to do that later tonight.

Fabby

if it is critical, you'll lose 4KB of data if the sector cannot be swapped out, but the error will be cleared and the block will be marked bad.

Faheem Mitha

I see this machine has been up 28 days.

@Fabby It's used for backup.

The external drive, I mean.

I wonder if I should just go ahead and buy another one. What do you think?

Fabby

@FaheemMitha :-) I understood from the first statement...

@FaheemMitha Nah! It's still in good condition.

@FaheemMitha 5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0

Faheem Mitha

@Fabby Ok. But isn't bad blocks a sign of failing health?

@Fabby Damn?

Fabby

@FaheemMitha Copy paste error.

Faheem Mitha

3:25 PM

Ok.

Fabby

You still have 60 blocks spare.

200-140=60

Faheem Mitha

@Fabby So the drive should mark the bad block as not to be used, and carry on?

Fabby

@FaheemMitha Yup.

Faheem Mitha

@Fabby Does that mean there have never been any reallocation?

Fabby

If you're lucky, the bad block just contains data that was read.

Faheem Mitha

3:26 PM

@Fabby Hmm. That's impressive if true.

@Fabby You mean backup stuff?

Fabby

@FaheemMitha You've had 140 re-allocations already.

Faheem Mitha

@Fabby Oh?

Fabby

@FaheemMitha As it is your backup drive: Yes.

Faheem Mitha

Oh, that's what that 140 means?

Fabby

@FaheemMitha Obviously...

>:-)

Faheem Mitha

3:27 PM

Not that obvious to me.

Fabby

@FaheemMitha Now it is...

@FaheemMitha Oops! My mistake!!!

Faheem Mitha

I see Tim is on the warpath.

Fabby

You've had 0!

:49626240 ID# ATTRIBUTE_NAME          FLAG     VALUE WORST THRESH TYPE      UPDATED  WHEN_FAILED RAW_VALUE
  1 Raw_Read_Error_Rate     0x002f   200   200   051    Pre-fail  Always       -       1
  3 Spin_Up_Time            0x0027   166   125   021    Pre-fail  Always       -       2666
  4 Start_Stop_Count        0x0032   100   100   000    Old_age   Always       -       447
  5 Reallocated_Sector_Ct 0x0033 200 200 140 Pre-fail Always - 0

Faheem Mitha

I really think he's in the wrong profession (though we don't actually know what profession his is).

Fabby

@FaheemMitha Huh? Anothe meta?

Faheem Mitha

3:29 PM

He should be a fiery muckraking political journalist taking on corrupt City Hall. I think they could make a TV series out of it. Or a musical.

@Fabby Check the election chat room.

Fabby

Or another question?

Faheem Mitha

@Fabby No, just a comment. Election chat room. Link on right.

I'm tempted to star it, but that might send the wrong message.

Fabby

@FaheemMitha Uhuh.

I've voted already and my most important criterium for a mod is: Have a great sense of humour!

Faheem Mitha

@Fabby Hmm. How can you tell?

Fabby

(Though many people here disagree with my stance)

Faheem Mitha

3:32 PM

@Fabby What stance is that?

Fabby

@FaheemMitha lemme find my answer (if it's not deleted in the meantime)

@FaheemMitha Because my definition of a sense of humour is: Be able to laugh with yourself and @JeffSchaller can...

Faheem Mitha

@Fabby Jeff seems like a cool dude. Though he might just be lulling us into a false sense of security, like Tim warns us.

Fabby

-7

A: 2019 Moderator Election Q&A - Question Collection

On a scale of 0-10, where: 0 = "none" 10 = "I could be a professional!" What is your sense of humour? :-)

Faheem Mitha

Maybe he's plotting to dissolve parliament and establish a dictatorship.

@Fabby Yes, I remember that one. It didn't seem to be a hit with the site.

You got +4 - 11, so some people did like it.

Fabby

@FaheemMitha Oh yes!!! Jeff is an actor and projects a false sense of goodness, but once he gets elected to be a mod he'll turn into a mad scientist!

and then smite us all going "mooahahahahaaah!"

:D :-) ;-)

Faheem Mitha

3:36 PM

@Fabby Yes, he's plotting to attack Nicaragua.

Fabby

:D :D :D

@FaheemMitha He's beyond the plotting stage: he's actually assembling the funds to be able to do it!

:D ;-) :D

@FaheemMitha Too few people have a sense of humour.

Faheem Mitha

@Fabby There are definitely worse things to have.

Fabby

And in the US, lots of people think they have a sense of humour, but they don't according to my definition...

@FaheemMitha Yes??? Like what?

Faheem Mitha

If you look at what is considered funny in US and British popular culture, there's kind of a wide gap.

@Fabby A strong urge to invade Russia, for example.

Fabby

@FaheemMitha That falls under "No sense of humour"

Faheem Mitha

3:41 PM

@Fabby Probably.

Fabby

@FaheemMitha 2 words:

Benny

and

Hill

>:-) ;-)

Faheem Mitha

In general UK comedies are at least occasionally funny, whereas many American things are best described as unfunny.

@Fabby Your two words don't mean much to me.

Fabby

Benny Hill - Joggers (1988)

►

Faheem Mitha

A good example of a show that actually is funny is the IT Crowd. But it's also quite English.

Fabby

@FaheemMitha Just noticed it got more downvotes than one of Tim's questions...

@FaheemMitha The problem is, I find most things funny...

E.G. Any funeral is funny after you've seen "Solyent Green"

Faheem Mitha

3:46 PM

@Fabby That's fairly dire. Some low-brow British stuff, I take it.

Fabby

@FaheemMitha Yup... 80s stuff. Like Monty Python.

Faheem Mitha

Well, that's the same nation that bought you "Keeping Up Appearances". Also "The British Empire". Neither of those were really funny.

@Fabby Well, Monty Python is funny some of the time.

Though too much falsetto.

Fabby

But Monty Python is absurd humour. This one is misogynistic...

Faheem Mitha

E.g. Life Of Brian, which is quite good, at least in parts.

Fabby

@FaheemMitha Yup...

Faheem Mitha

3:48 PM

@Fabby This Benny Hill thing?

Fabby

@FaheemMitha Yup.

Faheem Mitha

A once friend of mine once remarked something like - those Brits really know how to make movies.

Fabby

The series ever were "Not the 9 O'Clock news" and the Blackadder series IMHO.

Faheem Mitha

Though he wasn't specifically talking about comedy.

@Fabby I have mixed feelings about Blackadder. It depends too much on Atkinson insulting everyone in sight.

He's good at it, I'll give him that.

Fabby

@FaheemMitha "I've lost better friends last time I was deloused"

Faheem Mitha

3:50 PM

If I wanted to hire someone to insult me, I'd definitely go with Rowan Atkinson.

@Fabby For example.

But some of the stuff is effective. I don't remember much about it though. I haven't watched it in a very long time.

Fabby

That plan is as cunning as a fox who’s just been appointed Professor of Cunning at Oxford University.

Faheem Mitha

@Fabby That one, not so much.

terdon

@Fabby You cannot omit Fawlty Towers and Yes (prime)Minister.

Faheem Mitha

@terdon Yes to the former, of course. Never really been a fan of the latter. But I've got a feeling we've discussed it.

Fabby

@terdon I just told someone last week:

My name is Manuel, I'm from Barcelona, and I need nooothing!

terdon

3:57 PM

heh :)

Fabby

Looking forward to the new mods taking some of the work off your collective back???

AFK. BRB...

Faheem Mitha

4:09 PM

@Fabby Yes, someone else to argue with Tim.

Fabby

:-)

Faheem Mitha

That's a major downside of being a mod. Having to deal with difficult people. Or try to deal with them.

Earlier there was that kerfuffle with mike. I don't know if you were around then.

MikiBelavista

root@kali:~# vgs
VG #PV #LV #SN Attr VSize VFree
kali-vg 1 2 0 wz--n- 12.40g 20.00m

Faheem Mitha

@MikiBelavista Ok, that does not look promising. You're pretty much maxed out. 20M free.

Bear in mind, you can also enlarge your VG.

MikiBelavista

What should I do? I have done lextend

lvextend

Faheem Mitha

4:18 PM

@MikiBelavista How many disks do you have? And what are their sizes?

MikiBelavista

I will give you my fdisk

Faheem Mitha

Do you really just have one 12 GB disk?

@MikiBelavista No, lsblk instead.

Fabby

@FaheemMitha Nope, wasn't.

MikiBelavista

df -h
Filesystem Size Used Avail Use% Mounted on
udev 7,8G 0 7,8G 0% /dev
tmpfs 1,6G 2,1M 1,6G 1% /run
/dev/sda2 457G 48G 387G 11% /
tmpfs 7,8G 21M 7,8G 1% /dev/shm
tmpfs 5,0M 4,0K 5,0M 1% /run/lock
tmpfs 7,8G 0 7,8G 0% /sys/fs/cgroup
/dev/loop3 54M 54M 0 100% /snap/core18/782
/dev/loop2 3,8M 3,8M 0 100% /snap/gnome-system-monitor/51
/dev/loop0 13M 13M 0 100% /snap/gnome-characters/103

Faheem Mitha

@Fabby Ah, well that went on for awhile. Mike mostly seems to have left now, though.

MikiBelavista

4:20 PM

This is my Ubuntu host output

Faheem Mitha

@MikiBelavista lsblk, please.

MikiBelavista

loop0 7:0 0 13M 1 loop /snap/gnome-characters/103
loop1 7:1 0 86,9M 1 loop /snap/core/4917
loop2 7:2 0 3,7M 1 loop /snap/gnome-system-monitor/51
loop3 7:3 0 53,7M 1 loop /snap/core18/782
loop4 7:4 0 2,3M 1 loop /snap/gnome-calculator/180
loop5 7:5 0 140,9M 1 loop /snap/gnome-3-26-1604/70
loop6 7:6 0 14,8M 1 loop /snap/gnome-characters/206
loop7 7:7 0 13M 1 loop /snap/gnome-characters/139
loop8 7:8 0 14,5M 1 loop /snap/gnome-logs/37

Faheem Mitha

@MikiBelavista sda, sdb, and sdc are all really small.

MikiBelavista

What should I do?

Faheem Mitha

Are these physical HSDs?

MikiBelavista

4:24 PM

Yes

I have 2 SSDs

Faheem Mitha

@MikiBelavista Buy some bigger disks. Those are tiny.

MikiBelavista

One is 500GB

sda

Faheem Mitha

@MikiBelavista I don't see that in your listing.

MikiBelavista

sda 8:0 0 465,8G 0 disk
├─sda1 8:1 0 512M 0 part /boot/efi
└─sda2 8:2 0 465,3G 0 part /

Where are my VMs?

Faheem Mitha

@MikiBelavista That appears to say 8GB, unless I'm missing something.

Maybe someone else can help out? Am I perhaps going blind? I don't see any 500 GB.

MikiBelavista

4:27 PM

VBoxManage list vms
"minikube" {9c326ed5-faf4-42fe-acda-bf3a283f1a74}
"kalinew" {de6de631-0d51-4638-b967-66db463cbf05}

Yes,you are right,sorry

sudo fdisk -l /dev/sda2
Disk /dev/sda2: 465,3 GiB, 499568869376 bytes, 975720448 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes

Faheem Mitha

@MikiBelavista If you really have a 500 GB SSD, I suggest you check how you've set up your physical volumes.

MikiBelavista

Coomand?

Which command?

Faheem Mitha

@MikiBelavista Ok, I think I was confused by the commas.

That appears to be equivalent to a decimal point.

MikiBelavista

Yes,that is the big one.

Faheem Mitha

Ok. One sec.

@MikiBelavista What does pvscan say?

MikiBelavista

4:35 PM

sudo pvscan
No matching physical volumes found

Faheem Mitha

@MikiBelavista That's strange.

Oh, you're in the host?

MikiBelavista

Same output from Kali CLI

pvscan
PV /dev/sda5 VG kali-vg lvm2 [12.40 GiB / 20.00 MiB free]
Total: 1 [12.40 GiB] / in use: 1 [12.40 GiB] / in no VG: 0 [0 ]

The first one was host

Faheem Mitha

Your VB is Kali? What about the host? It's Ubuntu?

MikiBelavista

Yes,18.04

Faheem Mitha

I'm getting a bit confused. You have LVM enabled on VB, but not in the host?

MikiBelavista

4:40 PM

pvdisplay -m gives nothing

How to check this?

Faheem Mitha

@MikiBelavista LVM commands like vgs would return something if you configured LVM at all. Otherwise no.

Your Kali report /dev/sda5, but that doesn't show up in the host listing.

MikiBelavista

Ok,I think that I must reconfigure LVM

ANy tutorial how to configure LVM?

Faheem Mitha

What is df -h on the host?

MikiBelavista

df -h
Filesystem Size Used Avail Use% Mounted on
udev 7,8G 0 7,8G 0% /dev
tmpfs 1,6G 2,1M 1,6G 1% /run
/dev/sda2 457G 48G 387G 11% /
tmpfs 7,8G 69M 7,8G 1% /dev/shm
tmpfs 5,0M 4,0K 5,0M 1% /run/lock
tmpfs 7,8G 0 7,8G 0% /sys/fs/cgroup
/dev/loop3 54M 54M 0 100% /snap/core18/782
/dev/loop2 3,8M 3,8M 0 100% /snap/gnome-system-monitor/51
/dev/loop0 13M 13M 0 100% /snap/gnome-characters/103

Faheem Mitha

@MikiBelavista Ok, so what space did you allocate to your VB?

MikiBelavista

4:46 PM

I can not remember.

Faheem Mitha

@MikiBelavista Ok. You should check that. It looks like you have plenty of space. You just need to give enough to your VB.

MikiBelavista

I agree,thanks for your help.

Jesse_b

5:02 PM

@Kusalananda: I couldn't get very far

# for ((i=0;i<2097152000;i++)); do touch file$i; done
# set -- ./file*
# echo $#
7095901
# ls test/ | tail
ls: memory exhausted

It took several hours just to make those 7 mil files though

ilkkachu

@Jesse_b ewww

Jesse_b

@ilkkachu Heh it worried me too, I'm using a cloud container from work to test with and we had a server crash in that region around the same time

was unrelated though

Kusalananda

@Jesse_b Yeah, that's what I said in my comment. There is no limit other than the memory resource limits of the shell.

Jesse_b

@Kusalananda Yeah but from what I've read the max arg limit isn't related to the shell at all but just a process limit

Either way I was simply trying to find mine

which should be 2097152KB or 2097152000 characters

Kusalananda

When the shell calls execvp() to execute an external command, there's a different (and much lower) limit on the length of the argument list combined with the size of the current environment. On Linux, there's also another limit that limits the length of any one argument.

terdon

5:13 PM

@Jesse_b EEeek! Don't use a shell loop for that!

Kusalananda

@Jesse_b These numbers would depend on the amount of memory available to the shell.

Faheem Mitha

@Jesse_b I don't know what you're doing, but you could break it down into several loops.

Kusalananda

Or to a brace expansion piped to xargs

Faheem Mitha

@MikiBelavista BTW, consider using LVM on the host as well. LVM is useful technology if you want to change your filesystems.

And also software RAID is good for redundancy.

ilkkachu

@Jesse_b are you sure that's kB and not just bytes?

Faheem Mitha

5:18 PM

@Jesse_b For something like that, I'd probably use C or C++.

You're creating 2 billion files?

terdon

@Kusalananda The brace will still be pretty slow. I've been running this for two or three minutes:

time perl -e 'print "$_ " for 1..2097152000' | xargs -P 5 touch

And I'm already at >200M:

$ ls -lhd bar
drwxr-xr-x 2 terdon terdon 263M Mar 24 17:24 bar

Kusalananda

I'm not sure why you guys even have to try this...

terdon

@Kusalananda Curiosity?

Kusalananda

Well, ok.

terdon

I've been running an awk loop since just after Jessie posted that script, and it's considerably slower (of course):

time awk 'BEGIN{for (i=0;i<2097152000;i++){print > i}}'

$ ls -lhd foo
drwxr-xr-x 2 terdon terdon 3.8M Mar 24 17:25 foo

Kusalananda

5:25 PM

Then cat them all and you can say that "curiosity killed the cat"...

terdon

lol

Kusalananda

It's just a very slow way of finding out how much memory you have free.

terdon

memory?

Kusalananda

Yeah, I think the point was to test how big a glob set could take.

It depends on the amount of memory available to the shell.

So create 2097152000 filenames of a length of five bytes or so bytes.

That's 10.5 GB

Jesse has 10.5 GB free on his machine.

ilkkachu

Creating those files is mostly a filesystem test, I think

especially when you have a huge amount of them in a single directory

Kusalananda

5:30 PM

The exercise came from here:

@l0b0: The maximum amount of arguments is often upwards of 100k so it's probably unlikely to reach it if OP is planning to delete these files whenever they exceed 1000. — Jesse_b 4 hours ago

terdon

@ilkkachu Yeah, I ran out of inodes long before hitting any other issue.

Faheem Mitha

That's an adjustable parameter, I think.

ilkkachu

@terdon well, that, too, but I did mean the speed

@FaheemMitha also depends on filesystem :)

Faheem Mitha

@ilkkachu Does it?

ilkkachu

@FaheemMitha well, I mean that e.g. on ext4, you can't adjust the inode count on an existing filesystem, you can only set the number/density when creating the FS. But then if I've understood correctly, e.g. XFS creates them dynamically in any case.

terdon

5:44 PM

@ilkkachu hmm. Are you sure? The file creation speed should be constant, so the choice of how you generate the list of files to be created seems like the important point. The shell loop will always be much slower than something like the xargs + perl approach I posted.

And, of course, now I'm stuck figuring out clever ways to delete all those files. Thank you curiosity. And thank you @Jesse_b :P

Faheem Mitha

@ilkkachu Oh? I didn't know that.

And ZFS?

ilkkachu

6:08 PM

@terdon well, isn't it a question of what kind of a data structure the filesystem uses to store the directory entries. Creating a file also involves looking up if the same filename already exists.

Though as far as I understand, many filesystems use some kind of a tree, so lookup is just O(log n), not worse than that (but still not O(1))

(In theory, that is.)

terdon

@ilkkachu Are you sure? That will be the case for writing to a file, but will something like touch first check for the file's existence?

ilkkachu

@terdon if it calls open() on the filename, the FS has to check it. It needs to know if it's going to open the existing file, or if it has to allocate a new inode etc. (or if it should fail, if O_EXCL was used)

terdon

Hmm, yes makes sense. Thanks.

Faheem Mitha

How is btrfs doing these days? I haven't been tracking it.

Michael Homer

8:23 PM

There's no reason filename lookup can't be O(1), though it usually isn't

Faheem Mitha

Hey Michael.

Kusalananda

9:49 PM

Urgh, I can never remember how the current locale affects [[:alpha:]] vs. [A-za-z]...

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