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

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live dd over a mounted read-only root partiton

I'm trying to conceive a firmware update mechanism for a Linux-based embedded system without an additional initrd/initramfs/whatever. From within the running system which has a read-only mounted root ...
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1answer
307 views

How to install a .bin file that gives the error that it needs more space in /tmp?

Here is the error: ~]$ ./jdev_suite_121200_linux64.bin 0%....................................................................................................100% Not enough disk space in dir ...
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1answer
149 views

Access Windows File System From Linux OS

My sister's computer has stopped working. I am not entirely sure what the problem is, but I think it is a Windows/software issue. She really just wants to retrieve the pictures off it. I am ...
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1answer
141 views

How can I determine the cause of CF card corruption?

I installed qnx in my CF card and made it bootable and it was working well. However, yesterday it stopped working while my system was running. Checking the filesystem revealed that it was corrupted. ...
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2answers
4k 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?
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1answer
102 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?
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6k 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 ...
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1answer
260 views

Unreadable backup directory on a USB drive

The title pretty much sums it up. I was editing a script I wrote some time ago to automatically backup the contents of my Raspberry Pi SD card, and in the course of editing, I missed a "/", and so ...
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1answer
716 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 ...
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1answer
99 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 )
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2answers
95 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 ...
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1answer
160 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 ...
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3answers
1k 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. ...
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1answer
2k 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 ...
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4answers
218 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 ...
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2answers
2k 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 ...
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1answer
472 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? ...
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1answer
317 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 ...
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5answers
640 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?
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4answers
5k 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 ...
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3answers
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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 ...
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1answer
2k 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 ...
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2answers
3k 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 ...
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2answers
3k 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 ...
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1answer
3k 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 ...
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1answer
437 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 ...
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1answer
397 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 ...
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0answers
185 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 ...
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2answers
480 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 ...
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1answer
1k 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 ...
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1answer
44 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 ...
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0answers
80 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 ...
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1answer
599 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 ...
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3answers
650 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 ...
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2answers
1k 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
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3answers
885 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 ...
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0answers
423 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 ...
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1answer
94 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
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1answer
265 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 ...
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900 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 ...
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1answer
487 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 ...
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1answer
345 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 ...
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4answers
3k 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 ...
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3answers
83 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
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2answers
1k 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
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1answer
189 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 ...
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3answers
554 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 ...
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2answers
1k 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 ...
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1answer
1k 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 ...
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2answers
322 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 ...