A filesystem is a method of storing and organizing computer files and their data.

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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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Optimal rootflags for rootfs for ext4 file system running on USB thumdrive

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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Script to monitor folder for new files?

How do I detect new files in a folder with a bash script? I would like to process the files as soon as they are created in the folder. Is this possible to do so or do I have to schedule a script with ...
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188 views

What parts of the filesystem to tmpfs/squashfs/sparseimage for USB live system

I want to create a live system on a USB key / SDCard with Linux Mint 14 (KDE or Debian Edition) that stores data persistently. The USB key needs to have at least one fat32 partition. As storage for ...
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14 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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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 ...
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30 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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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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706 views

Sphinx Search shutting down after `FATAL: accept() failed: Too many open files`

I'm running Sphinx Search Server V2.06 ( the latest stable release ) on an Amazon EC2 with Linux CentOS. In general it is running fine, but the searchd.log is showing this error over and over with ...
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Why are there so many different ways to measure disk usage?

When I sum up the sizes of my files, I get one figure. If I run du, I get another figure. If I run du on all the files on my partition, it doesn't match what df claims is used. Why are there so many ...
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686 views

Which file system to choose for small sized files?

I have a partition and it has ~100 GB of audio files. Most of them are mp3 or ogg, each has size of ~15 MB. I update it on a weekly basis. Right now, the partition is formatted as ext4. I have read ...
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29 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 ...
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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, ...
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76 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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23 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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3k views

ext3 root filesystems goes read-only with aborted journal even after repairs

Short version: ext3 root filesystem on rackspace (xen) VM detects aborted journal on boot and mounts read-only. I've attempted to repair this from a rescue environment with tune2fs and e2fsck as ...
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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]; ...
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Can I configure my Linux system for more aggressive file system caching?

I am neither concerned about RAM usage (as I've got enough) nor about losing data in case of an accidental shut-down (as my power is backed, the system is reliable and the data are not critical). But ...
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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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23 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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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 ...
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How is busybox and rootfile system related? [closed]

I often see they talk about busybox and root file system together. busybox has binaries for ls, cp, mv etc. How are the two related? For example here Although the BusyBox versions of these ...
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Why is dd so slow on raw device, so fast on filesystem (writing on USB key)?

I have a USB key that I am trying to benchmark quick'n'dirty on Linux. dd on raw partition I'm testing write bandwith. I created a partition starting at sector 2048, then did a 4 GB sequential ...
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38 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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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 ...
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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?
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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 ...
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385 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 ...
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2k views

How to clone/copy all file/directory attributes onto different file/directory?

I want to copy the attributes (ownership, group, ACL, extended attributes, etc.) of one directory to another but not the directory contents itself. This does not work: cp -v --attributes-only A B ...
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274 views

Find where inodes are being used

So I received a warning from our monitoring system on one of our boxes that the number of free inodes on a filesystem was getting low. df -i output shows this: Filesystem Inodes IUsed ...
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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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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) ...
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524 views

Querying an overlayfs

I'm looking for a way to query a mounted overlay filesystem (overlayfs) in order to check it's upper and lower directory, but until now I haven't found any suitable command for that. Is there is a way ...
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139 views

How to backup (make a copy of) LiveCD changes?

Many LiveCD distributions (for example Lubuntu 12.10 I use) allow making changes, for example updating timezone, logging in to Google Chrome, updating and installing additional packages such as ...
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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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Space left on Linux RAM/TMP,FS

Recently I have come to believe a number of unusual occurrences that have happened while running a Parted Magic Live CD, are the result of running out of space on the RAM based filesystem, namely: ...
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40 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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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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Virtual write-only file system for storing files in archive

I have an embarrassingly parallel process that creates a huge amount of nearly (but not completely) identical files. Is there a way to archive the files "on the fly", so that the data does not consume ...
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7k views

Clear unused space with zeros (ext3,ext4)

How to clear unused space with zeros ? (ext3,ext4) I'm looking for something smarter than cat /dev/zero > /mnt/X/big_zero ; sync; rm /mnt/X/big_zero Like FSArchiver is looking for "used space" ...
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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.
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217 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% / ...
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Where is filename stored on a filesystem?

Where is filename stored on a filesystem? It's not in inode or with the actual file content since we have hard link that two filenames can point to the same inode.
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274 views

File system CRC check

I know that before running the kernel, u-boot (the boot loader) will check the kernel image CRC. Only if it is correct it will go further, else it will give a "Bad CRC" error. I want to do same thing ...
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479 views

Preventing access blocking while external HDD spins up?

I have an old laptop where I installed Debian along with a samba server which I am using to share read-write access to 4 external hard drives, which I use to stream my media from. All works fine, ...
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Why store program code in /var/cache?

I have inherited a Java / Tomcat stack, running on Ubuntu. It has crashed and I am trying to restart it. The program code seems to be using a config file which I have found on the file system. The ...
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What doesn't need defragmentation? Linux or the ext2 ext3 FS?

Why don't you have to defrag a Linux system? Because it's using the ext2/ext3 file system or because it's Linux? That's relevant, because a have a double boot system (W7 / Ubuntu) and a common ...
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37 views

Unable to format a CF card

I have a compact flash card formatted to FAT16. I am unable to format it to any other file system. I used GParted to format the card to ext2 for example, after I do that, the file system becomes ...
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rootfs.jffs2 files system won't fit in mtd3

I have a files system that I am trying to put in flash memory mtd3 partition. I first boot using uboot and then do run sdboot to boot using SD card as shown below: U-Boot-PetaLinux> ...
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Listing script's file dependencies

Given a shell script, is there an easy way to extract what files it manipulates explicitly (so not like concatenating some command and than eval-ing it)? E.g. #!/bin/bash . /etc/someconfig.cfg ...