1
vote
1answer
39 views

Best parameters for ext4 filesystem to handle virtualbox disk images

I have ext4 partition, which holds disk image files VirtualBox works with. They all are fixed-size images (i.e. files never change their size). They are defragmented as much as possible (with ...
1
vote
1answer
80 views

File has bytes - appears to be empty

I'm having the following problem: Some text files (also some binary files) on my system are listed with the correct file size but when I open them, they appear empty. >ls -la -rw-rw-r-- 1 user ...
4
votes
1answer
47 views

“hard-linking” parts of a big file in which only a small part has changed

I use rsync to make backups: rsync -a --link-dest=PATHTO/$PREVIOUSBACKUP $SOURCE $CURRENTBACKUP This way I save space due to using hard links. The problem appears when I need to backup a huge file ...
2
votes
2answers
162 views

Merging /usr/bin and /usr/sbin into /bin (GNU/Linux)

I've read quite a number of discussions about people wanting to merge /bin and /sbin into /usr/bin. The same cannot be said for doing it the other way around. Is there any technical reason why one ...
3
votes
2answers
124 views

File system that never breaks (data loss acceptable)

There're several existing topics revolving around this issue, but what I seek is slightly different. I have an sd card on an embedded Linux and it suffers from power loss. I might be able to modify ...
9
votes
2answers
142 views
+100

On system memory… specifically the difference between `tmpfs,` `shm,` and `hugepages…`

I've been curious lately about the various Linux kernel memory based filesystems. Note: As far as I'm concerned, the questions below should be considered more or less optional when compared with a ...
1
vote
0answers
29 views

How to use fslint (in particular findnl) on the command line to actually mimic the behavior of the fslint-gui?

So I am trying the fslint tools. However, the help included in those tools as well as the man page don't indicate that the cleanup actions offered by the fslint-gui are also available through fslint ...
3
votes
1answer
51 views

ext4, why 70k file takes 88 blocks

[root@xx]# cat -n create_extents.sh 1 #!/bin/bash 2 3 if [ $# -ne 2 ] 4 then 5 echo "$0 [filename] [size in kb]" 6 exit 1 7 fi 8 9 ...
4
votes
3answers
115 views

Hidden Files&Directories in user's home directory [closed]

I am in my user's home directory, I do: ls -a Then it shows me large number of hidden files and directories in my user's directory. Which of them I am allowed to remove? Which ones are necessary ...
1
vote
1answer
87 views

File monitoring to pre-empt hacker

We have a hacker occasionally attempting to hack a site, and so far unsuccessful, but I would like a way to determine if the site has been compromised (i.e., files edited). The type of attacks are LFI ...
1
vote
0answers
38 views

How can i determine the block size of an vxfs filesystem?

I am looking for a way to see what the current blocksize of an filesystem is. Normaly i would use tune2fs -l | grep "Block size", but that doesn't work on vxfs. I googled a bit and found fstyp -v ...
0
votes
1answer
41 views

Recovering truncated file

I'm in a peculiar situation. While editing a Perl program I accidentally truncated the file to zero length (using an Emacs lisp code I was developing). I need to recover that program... How do I that ...
5
votes
1answer
106 views

Cannot delete broken symbolic link

I have a symbolic link formerly pointing to a Dropbox directory. I don't know what I did wrong, but apparently now it points to itself. hyper@mypi:/home/hyper/test$ ls -l total 1024 lrwxrwxrwx 1 ...
0
votes
1answer
16 views

mke2fs difference between -i and -I options

sudo mke2fs Usage: mke2fs [-c|-l filename] [-b block-size] [-C cluster-size] [-i bytes-per-inode] [-I inode-size] [-J journal-options] [-G flex-group-size] [-N number-of-inodes] [-m ...
3
votes
2answers
94 views

Linux file system that ages off older files when partition is full

I am wondering if there is a file system equivalent to a round-robin database, which for a fixed size, ages off the oldest files. It is pretty easy to implement with a simple cron job, which I have, ...
1
vote
2answers
50 views

Something like a symbolically linked file, but with change details attached?

Is there a file type or method for using files in which certain files look and behave like symbolically linked files, but contain extra meta information for changing the data when they are read? ...
2
votes
2answers
80 views

Resize vdi size doesn't work as supposed [duplicate]

I just installed the new one Debian xfce via VirtualBox, but decided to increase the vdi size from 8GB to 20GB (because it requires 42% of all disk space at this moment): VBoxManage.exe modifyhd ...
2
votes
4answers
119 views

What is the /dev/disk/by-uuid/ and why does it use all free space on the disk

I have the following Debian that works in Virtual Box: $ uname -a Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.51-1 x86_64 GNU/Linux Recently I notice that I don't have any free space: $ df ...
5
votes
2answers
149 views

How to create a fixed size Linux ramdisk which does never swap to disk?

I want to create a fixed size Linux ramdisk which never swaps to disk. Note that my question is not "why" I want to do this (let say, for example, that it's for an educative purpose or for research): ...
1
vote
1answer
60 views

Monitor file access count by user

I have written a script which is deployed just by putting it in a globally accessible location for all users. I want to log the usage of this script. Is there a way in Linux to find out how many ...
4
votes
2answers
228 views

Why is dd using direct slower writing to disk than to a file

I am trying to compare aggregate write rates when writing to a file in a GPFS file system, as compared to writing directly to a disk on a system with Red Hat Enterprise Linux Server release 6.4 ...
1
vote
1answer
150 views

fstrim trims more than half of partition size even though partition mounted with discard

When I installed my SSD I just mounted with discard and didn't sweat it. However today I was reading about the pros and cons of using fstrim instead and decided to run the program to get an idea of ...
3
votes
1answer
58 views

Something like VMware “Changed Block Tracking” (CBT) in linux

I'm wondering if is there any possibility to track changed blocks in linux with an ext3/ext4 filesystem (or a specific one supporting it). I mean a feture like the Changed Block Tracking (CBT) ...
0
votes
3answers
128 views

How are filesystem snapshots different from simply making a copy of the files?

by doing this, # btrfs subvolume snapshot /mnt/1 /mnt/1/snapshot # tree /mnt/1 /mnt/1 ├── a ├── snapshot │ ├── a │ └── subv └── subv └── b 3 directories, 3 files We can create snapshot ...
0
votes
0answers
41 views

Big file overwriten with a 0B file

I just opend for write (by mistake) a big file with data (about 200 MB). Now I have this file and it has 0B. I want to know If I can find raw data on disk for recovery... ?
0
votes
1answer
278 views

Elementary OS System Settings has disappeared

I don't know how this happen. Part of the system setting has disappeared. How have any idea to restore them ?
0
votes
3answers
179 views

noexec on /tmp and /var/tmp directory

Our client servers are running old version of jboss (Jboss 4.0) which has lots of known vulnerabilities. Result is that the server is hacked and we are seeing some unknown executables running from ...
6
votes
2answers
108 views

Linux File Versioning?

We are migrating from A VMS environment to a Linux environment for some old alpha servers we are decommissioning. The one challenge I have not been able to overcome is file versioning. VMS keeps ...
2
votes
1answer
66 views

Process overwrite access restriction

I want to run a program so that it can only create new files and not overwrite existing ones. Does something like this exist? $ fsaccess --can read,write --not overwrite --command bash -c 'echo ...
0
votes
1answer
40 views

Will stat() cause an actual harddisk access or is the information cached?

While optimising my PHP opcode caches, I tried alternating the stat setting ( = the opcode cache checks, whether a file was modified via stat(), before using the cached results). But I did not see ...
3
votes
1answer
92 views

Is there a way to show all flags in /proc/mounts?

Some filesystem flags seem to be hidden in /proc/mounts, depending on whether they are defined as defaults. Is there a way to show all flags in /proc/mounts, also including the default ones? And if ...
1
vote
1answer
56 views

Create Relative Symlink Inside Relative Symlink

I've been browsing for a minute now trying to find a way to create a relative symlink inside a relative symlink, and what I mean by that is this... I have my CakePHP Templates Skeleton as a symlink ...
1
vote
1answer
116 views

what are the different ways to set file permissions etc on gnu/linux

On Unix a long time back I learned about chmod to set permissions and to allow programs to gain privileges. I have recently discovered extra commands on GNU/Linux: chattr, setfacl, setcap. Are there ...
0
votes
2answers
83 views

File compression - how to implement in Linux

I would like to be able to compress certain files (that I need to keep, but use rarely) on disk. I noticed that chattr +c flags a file for compression, but it doesn't seem to actually compress files. ...
0
votes
0answers
53 views

How to compare two rfs directories with `diff`?

I've two RFS (RFS = Root File System) directories, which I would like to compare to each other with diff. Both directories represent an RFS of some other system, and they may contain links. If those ...
1
vote
4answers
142 views

how to tell if a partition is empty/unused

This is certainly a really easy question for you all I am sure. So I have Ubuntu (13.04) as the only OS mounted on my HDD. What I would like to do is re-partition my HDD so as to begin a LFS build. ...
3
votes
4answers
288 views

Find which process is modifying a file [duplicate]

A specific file on our production servers is being modified at apparently random times which do not appear to correlate with any log activity. We can't figure out what program is doing it, and there ...
2
votes
1answer
74 views

How can I determine the date when a piece of software was installed from source?

I've been asked to find out when a specific version of software was installed. The only thing I have to go on are the modification times of the directories in question. I'm having a hard time ...
14
votes
2answers
388 views

Can I list the filesystems a running kernel can support?

I'm trying to detect what filesystems a kernel can support. Ideally in a little list of their names but I'll take anything you've got. Note that I don't mean the current filesystems in use, just ones ...
3
votes
1answer
661 views

USB Media filesystem problem

My USB is not detected recently, I tried mount, fdisk, dd, gparted, mkfs.vfat :~# tail -f /var/log/syslog Oct 27 12:54:29 mohammad-Inspiron-N5110 kernel: [18843.105772] usb 3-2: New USB device ...
2
votes
5answers
262 views

How can a filesystem be copied exactly as is?

I have a file system for a device I am programming that I would like to make an exact copy of. Ideally I would like this copy to be identical to the folder that it was copied from. I have tried using ...
0
votes
1answer
251 views

No Space left on device - Debian

when Im new to linux and try to run this below code apt-get -f install getting below error: Checking the available space df Tho output How to increase the available space in /usr path?
3
votes
1answer
158 views

On Linux, can you write to HFS+ extended attributes?

I'm in the process of setting up a file server, and I'm looking for a way to preserve extended attributes in files that come from OS X machines, and manipulate them while the file is on the server. ...
2
votes
1answer
55 views

relocate ext4 structures to survive truncation

I have a 6Gb raw disk image with 1 ext4 partition on it. I have only 1Gb worth of data on it Is there a way to reposition/adjust ext4 datastructures such that I can truncate the disk at 1 GB or 1.2Gb ...
0
votes
1answer
793 views

How to install squashfs-tools on Ubuntu?

I tried running `unsquashfs and got: $ unsquashfs filesystem.squashfs The program 'unsquashfs' is currently not installed, You can install it by typing: So I went to install it: $ sudo apt-get ...
0
votes
0answers
18 views

UBUNTU + extract filesystem.squashfs for editing [duplicate]

please advice how to install the squashfs-tools on UBUNTU linux ? I try this unsquashfs filesystem.squashfs The program 'unsquashfs' is currently not installed, You can install it by typing: ...
2
votes
3answers
224 views

Where is ACL data technically stored?

I'm studying ACLs and am confused on where this information technically resides. Is this just technically just meta data from inodes?
1
vote
1answer
35 views

Why can't ACLs block users from having access to their own home directory?

CentOS 6.x In the process of studying ACLs, I came across this blurb in my training documentation: However with ACLs, you can't deny access for a user to his home directory While I can't think ...
0
votes
1answer
87 views

Recover from ext2 filesystem corruption

I have a TinyCore (3.6) Linux distribution on a device of mine, which uses disk-on-module or compact flash storage. The filesystem is ext2. I have a LAMP stack on this device and I'm playing with a ...
1
vote
1answer
81 views

How does my partition (ext4) know its size of used/free space?

I ran df, and the output appears almost instantly: (FS Size Used Avail Use%) /dev/sda1 145G 8.4G 130G 7% sda1 is an ext4 partition. Without summing the size of all files, how can ...