A filesystem is a way to organize and store computer files with their data.

learn more… | top users | synonyms (2)

2
votes
3answers
524 views

What is the difference between path and directory?

I don't understand the difference between path and directory. Could someone explain to me with examples?
1
vote
1answer
34 views

backup inode table on ext2/3/4

is it possible, to backup on regular basis inode table (including all inode information) on ext2/3/4? If yes, how to do it, or which program to use?
14
votes
4answers
1k views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
5
votes
1answer
322 views

Kernel panic when passing noatime in bootargs

I have an embedded system using jffs2 and want to pass rootflags=noatime in the kernel bootargs parameter. This results in a kernel panic: jffs2: Error: unrecognized mount option 'noatime' or ...
2
votes
1answer
53 views

How can I partition and format my disk to an accuracy of “LBA” by commands?

How can I partition /dev/sdb into /dev/sdb1 and /dev/sdb2, and then format /dev/sdb1 to exFAT ( or FAT32 ) from LBA=1 to 2097152 by commands? ( LBA=0 is reserved for MBR )
0
votes
2answers
76 views

Shrink btrfs from /dev/sda to /dev/sda1

suppose I have 2 btrfs filesystems: one mounted on /mnt/big spanning across /dev/sda /dev/sdb /dev/sdc /dev/sdd the other mounted on /mnt/small on a single drive: /dev/sde How would I shrink the ...
3
votes
1answer
88 views

How to evaluate if it's worth using deduplication?

I have a partition where I am considering to use deduplication. For the profile of it's data I think it will be a good choice. Still, before doing it, I would like to evaluate the impact in a more ...
1
vote
3answers
299 views

File missing after fsck

Recently, my HDD crashed and I had to run a fsck command. Many files were moved to the lost+found folder and I've retrieved the important ones using find and grep, but I can't find my SQL databases. ...
3
votes
1answer
549 views

Booting using initramfs instead of uramdisk

I am working on Zynq Microzed board. It is booting perfectly with uramdisk.image.gz but I trying to boot it with initramfs.cpio. In this regard I have made following changes in header files of ...
1
vote
4answers
122 views

Hiding data in filesystems

I want to hide some files such that not even 'ls -a' can find it. I'm not talking about adding '.' in front of the filename. I was thinking if I could create separate system calls for accessing those ...
3
votes
2answers
1k views

Make part of read-only filesystem writable

I have a filesystem on flash using jffs2. I would like to mount this filesystem read-only, except for a single folder that I would like to be writable. Is this possible without resorting to something ...
3
votes
1answer
129 views

Does du or df perform caching?

I was wondering if there is any caching done with these utilities. I assume not, but not positive. Are there any typical similar utilities that do use caching to speed up results on subsequent runs? ...
3
votes
1answer
72 views

filesystem that works under qemu and I can mount on my host

I'm using qemu for different kind of tasks, I would like to pick a filesystem that is both qemu-compatible and easy to mount under my host. I already discarded both qcow and qcow2 because apparently ...
11
votes
5answers
536 views

Is there a more succinct alternative to piping to wc for counting files in a directory

If I do ls -1 target_dir | wc -l, I get a count of files in a directory. I find this a bit cumbersome. Is there a more elegant or succinct way?
1
vote
4answers
928 views

How to check physical device contents

I got a server with 2 hard drives. I would like to know what is on 2nd drive. How would I list all contents on physical device ? lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT xvda 202:0 0 ...
9
votes
3answers
2k views

EXT3: If block size is 4K, why does ls -l show file sizes below that?

If you run ls -l on a file that contains one letter, it will list as 2B in size. If your file system is in 4k blocks, I thought it rounded files up to the block size? Is it because ls -l actually ...
0
votes
0answers
75 views

Unable to make file system writtable no matter what

I have a flash card SanDisk of a camera which I plug in into my computer: $ lsblk mmcblk0 179:0 0 3.7G 1 disk └─mmcblk0p1 179:1 0 3.7G 1 part $ mount /dev/mmcblk0p1 on ...
1
vote
1answer
187 views

How to make an unallocated space “exist”?

I have Ubuntu and Windows installed together. I'm going to install Arch also along with them. For now, I what them to live there all together in my computer. I have the following: I'd like to ...
2
votes
2answers
1k views

Unable to remove the files from an usb drive (neither by dd /dev/zero nor by rm -r)

I have a flash usb drive and up till now it has worked well. Recently I recorded iso to it using dd. Now I want to delete it. $ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT ....... sdb ...
6
votes
2answers
1k views

“Converting” a filesystem from ext3 to ext4

I've read on some Q&A on this website that one can "convert" an ext3 filesystem to ext4 without formatting, by issuing tune2fs -O extents,uninit_bg,dir_index /dev/dev-name And then running ...
4
votes
1answer
973 views

How to reset password on an encrypted fs?

I've got a laptop which I haven't used since the last summer vacation: I did put Debian 7 on it and used Debian's feature to fully encrypt the disk, besides a tiny bootloader (or a tiny partition) I ...
1
vote
1answer
185 views

Files that do not exist, prevent me from deleting them, corrupted filesystem

Well... It's about on an OS X system (hfs+), but that's unix after all to. :p system has become unbootable, due to a filesystem error... fsck.hfsplus fails because .... ... ** Checking ...
1
vote
1answer
131 views

Starting my own application at the startup

I am working on zc702 board having ARM Cortex A 9 processor. I have a binary that I got after cross-compilation for ARM (LED blinking). Now I want that this file should execute as soon as the the ...
3
votes
0answers
101 views

Optimal rootflags for rootfs for ext4 file system running on USB thumdrive [closed]

I have made myself a bootable USB Debian 7 thumbdrive, using debootstrap. It boots nicely - but occasionally freezes for a bit. I can see the load average is much higher than the running tasks should ...
1
vote
2answers
121 views

How can I find out about “rootfs”

Running Debian 7; when I execute a cat /etc/mtab I can see all sorts of useful information about the filesystems that are mounted, such as the filesystem and options used to mount then; however ...
2
votes
1answer
456 views

Why do deleted files continually reappear?

I've been having a strange issue recently, where I would delete files from a location (i.e. Desktop), and then empty the Trash. However, a day or so later (I'm not sure exactly what triggers it), the ...
0
votes
1answer
27 views

What is the encryption function in Encfs?

I'm a newbie at Encfs. After I read a paper about Encfs, I figured out there is a Encryption layer in Encfs. So I tried to find exact encryption function. but I couldn't find that because there are ...
1
vote
0answers
30 views

How is default readahead value determined

I have two different devices running XFS and the default readahead value set differs between the two disks. Why is that ? How is the default size computed ? Is it device dependent ? I might also add ...
4
votes
1answer
194 views

Backup of a ubi file system with dd?

A have a root file system (file system - image containinf folder structure and content) on a flash drive. The flash drive uses UBI as the underlying file system file system - the way the data blocks ...
5
votes
3answers
230 views

What filesystem metadata operations are actually journaled in ext4 & xfs?

I can't find a simple, straight answer about which filesystem metadata operations are actually persisted to the ext4 & xfs filesystem journals. Note that I am not inquiring about what POSIX ...
3
votes
2answers
446 views

Moving unallocated space from Extended partition to create a Primary partition

This is my partition structure : I want to create another primary partition from that unallocated space. If I shrink sda2 to a size less than what I needed for to create another primary partition, ...
3
votes
3answers
309 views

Speed up copying 1000000 small files

I have 1000000 4-20 kb files in a dir. I need to copy that dir. But it seems I have to do a seek for each files so this takes quite a while. Is there a way in which I can speed this up? I am ...
1
vote
0answers
191 views

Replacing default initramfs with my own

I followed this article to develop my own sample intramfs.cpio Now I have to put this in my kernel and compile. The procedure that I follw for petlinux is that I first run petalinux-config (and ...
1
vote
1answer
42 views

The libblkid library: any way to use it with blocks in the core memory?

I know how to use the libblkid library to analyze existing block devices. I'd like to use it to analyze a memory extent before I write it to the block device. Something like that: char block[4096]; ...
2
votes
1answer
74 views

The libblkid library: what is the 'blkid_superblocks_get_name' function for?

I'm trying to use the libblkid library to analyze various filesystems on a block device from a C/C++ program, and it works well. However I'm confused with the blkid_superblocks_get_name function from ...
8
votes
8answers
850 views

Do I require a file system when I do not want to store any data

I asked a question here Is it mandatory to have a file system One of the comments is : how a system without file system would work on linux as even a printer or ethernet card is considered as ...
1
vote
1answer
226 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
177 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 ...
0
votes
0answers
356 views

No filesystem could mount root, tried: jffs2

CPU: ARM Cortex A-9 This is the kernel command line that I appears in configuration menu root=mtd:jffs2 rw rootfstype=jffs2 console=ttyps0,115200 I have put three files in flash: BOOT.BIN in mtd0 ...
2
votes
4answers
903 views

Why is writing SLOW on raw device, and FAST on filesystem (USB key)?

I have a USB key (PQI U822V-Speedy 32G) that I am trying to benchmark quick'n'dirty on Linux. I'm testing write bandwith. dd on raw partition I created a partition starting at sector 2048, then did ...
0
votes
3answers
49 views

Verify semantic integrity of filesystem

I just started up my linux box to find that one of my filesystem's had errors: I had to login as root to run fsck and hit y repeatedly. There were a lot of errors. So many that I used silly putty and ...
13
votes
2answers
555 views

Is that possible to integrate zip and tar.gz files as directory into the file system

I wonder if there is a way to integrate (it's a bit different from mounting, I think) compressed files as directories into the file system? E.g., one could download a compressed-file.tar.gz to his ...
3
votes
1answer
100 views

ext4 inode size, shown by dumpe2fs

Manpage about mke2fs says "mke2fs creates 256-byte inodes by default". I've formatted my small (320MB) test partition with command: sudo mkfs -t ext4 /dev/sdc1 The defaults for the mke2fs are ...
0
votes
3answers
207 views

Most accurate disk usage report? [duplicate]

Since disk space is allocated in blocks, is it a more accurate representation of the actual space consumed by a directory to report it in blocks vs bytes? If a file of size 1,025 bytes resides on a ...
5
votes
2answers
630 views

ext3 Filesystem shows full to most apps, but only 77% full to DF

Var is showing as full to many apps like Nagios, Puppet, and the LVM tools (pvs, vgs, etc) df -h output 6.0G 4.3G 1.4G 77% /var vgs output /var/lock/lvm/V_rootvg:aux: open failed: No space ...
1
vote
1answer
358 views

Ext2 block structure: size of reserved GDT Blocks

In every publication I found about ext2, the structure of a block group is defined as following: Super Block: 1 block Group Descriptor: N blocks Data Bitmap: 1 block Inode Bitmap: 1 block Inode ...
3
votes
2answers
136 views

Monitor when read/write on metadata or mmaped files hit the disk

On a server hosting a wide range of websites, I often see IO becoming a bottleneck without being able to identify the processes responsible of IO operations with tools such as iotop, iostat or sar. I ...
2
votes
5answers
254 views

Get space details without drive names

if there a way to get drives space details without drive names. E.g., the output of df -h Filesystem Size Used Avail Use% Mounted on /dev/sda3 20G 15G 4.2G 78% / ...
6
votes
2answers
2k views

what does it mean by cold cache and warm cache concept?

I read a paper and it used terms “cold cache” and “warm cache”. What does it mean by cold cache and warm cache concept? I visit this but I need something more.
23
votes
5answers
3k views

How to tell which file is original if hard link is created

For example, I have a file myold_file. Then I use ln to create a hard link as mylink: ln myold_file mylink Then, even by using ls -a, I cannot tell which is the old one. Is there anyway to tell?