Questions tagged [filesystems]
A filesystem is a way to organize and store computer files with their data.
904
questions with no upvoted or accepted answers
10
votes
1
answer
628
views
Why does ZFS rollback destroy intermediate snapshots?
Having used btrfs before, I was surprised to find out that rolling back a snapshot in ZFS not only changes the “working set” of files, but also requires that any snapshots which are newer than the ...
- 331
9
votes
2
answers
1k
views
How do I layer compression on top of encryption on top of BtrFS, per-file?
BtrFS should support this really, but it doesn't. So ECryptFS looks like it will fill the gap. The only thing is, how would I layer compression on top of this?
Reasons for compression on top of ...
- 719
8
votes
0
answers
2k
views
Why are block sizes limited by page size in Linux?
In many (all?) file systems that Linux uses, including ext2/3/4, the maximum block size is the page size of the architecture Linux is running on, ie. 4KiB on x86. Why is there this limit? Might this ...
- 611
7
votes
0
answers
431
views
no such file or directory trying to list or remove file in btrfs
I have a file system mounted btrfs. I have one directory in particular, that I can't remove, because it's listed as non-empty. In that directory, there's one file, which I can see the name of, but ...
- 387
7
votes
0
answers
4k
views
OverlayFS - How to make changes to upper filesystem persistent without unmounting?
I am using an USB drive to start a linux system which needs changes from time to time and also writes some logs. Flash drives tend to fail early if there are many write operations. That brought me to ...
- 361
6
votes
0
answers
140
views
How to guarantee temporary immutability of LVM2 LV at raw block level?
I inherited an Azure VM (Ubuntu 20.04) which has a 7 disk VG fully occupied by a RAID5 LV formatted as ext4.
I need to take backups and was hoping to use Azure Backup to snapshot the Azure Disks ...
- 61
6
votes
1
answer
162
views
btrfs "unable to zero output file"
I'm trying to create a btrfs file system with a single volume from a directory 'root', over mtd and nandsim.
With a few token files and directories in my root directory, and successfully created and ...
- 111
6
votes
0
answers
5k
views
Using dd on Mac OS: conv=fsync equivalent?
I'm running an experiment where I benchmark the speed of reading and writing with and without caching. On Linux, using 'conv=fsync' as an operand makes sure that the output file is entirely physically ...
- 61
6
votes
1
answer
4k
views
Wrong inode: corrupted f2fs, fsck.f2fs cannot repair
A f2fs partition on my Android phone has recently become corrupted. It will still mount fine; however, I completely lost access to one directory (/data/media/0), which now shows as empty. Yet the disk ...
- 113
6
votes
0
answers
1k
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 ...
- 161
5
votes
0
answers
3k
views
How dangerous is "Free blocks count wrong"?
I ran fsck in read-only mode and got some errors like this :
Free blocks count wrong (5597728, counted=5231480).
Fix? no
As stated here :
Free Block Checks
Free blocks are stored in the cylinder ...
- 1,070
5
votes
1
answer
13k
views
Partition #3 contains a ext4 signature
When i use fdisk to create a new partition i get an error which says
Partition #3 contains a ext4 signature
Do you want to remove the signature? [Y]es/[N]o:
This error is not a problem but i am ...
- 967
5
votes
1
answer
568
views
How can I find what a process is trying to watch using strace, lsof, and fdinfo?
I have a process (the NewRelic infra agent) that is hung on a RHEL 7, xfs filesystem host. I'm thinking that it's trying to watch a file or maybe a socket that another process already has in use.
...
- 151
5
votes
1
answer
2k
views
Disable writeback cache throttling - tuning vm.dirty_ratio
I have a workload with extremely high write burst rates for short periods of times. The target disks are rather slow, but I have plenty of RAM and very tolerant to instantaneous data loss.
I've ...
5
votes
1
answer
19k
views
ext2fs_open2: Bad magic number in super-block
I'm trying to resize a Linux partition, but after tweaking a lot with this disk I don't know If I have totally corrupted it.
Device Boot Start End Sectors Size Id Type
/dev/sdd1 * ...
5
votes
1
answer
5k
views
using overlay2 on CentOS 7.4
How do I install and enable the overlay2 storage driver on CentOS 7?
I have done many google searches on this and I see that version 7.4 is required. So I typed the following commands to confirm ...
- 5,149
5
votes
0
answers
5k
views
are we going to get a linux module for APFS?
ExFAT doesn't support symbolic links on linux. My git repositories are getting corrupted if I use them on exfat removable media between linux and macOS. Is there any work going on to support APFS on ...
- 996
5
votes
0
answers
817
views
Problem copying a directory larger than 6 GB
I have a problem when I want copy a directory to a disk external, but the directory has size 6 GB.
When try copy it, it gives me a error: " File too large",
I give more information, that directory ...
- 53
5
votes
0
answers
4k
views
Disk I/O latency using /proc/vmstat file
How do I calculate disk read and write latency in Linux?
Is it possible to do the calculation using /proc file system?
I am using iostat and vmstat command. But I do not understand how the ...
- 2,618
5
votes
2
answers
2k
views
How to mount this disk? (EBS)
I restored an EBS volume and attached it to a new EC2 instance. When I lsblk I can see it under the name /dev/nvme1n1.
More specifically the output of lsblk is:
NAME MAJ:MIN RM SIZE RO TYPE ...
- 1,485
4
votes
0
answers
923
views
When does Linux flush data to the disk?
I know that usually the answer to this question is "when it sees fit", or some other obscure answer. And many times I saw that if the host gets hard booted, some of files that got recently ...
- 4,025
4
votes
0
answers
1k
views
Can dm-crypt (LUKS2) be implemented on top of an UBI volume on a raw NAND flash?
If I have an embedded system with a raw NAND flash, with a bad blocks table etc., as I understand it, the best way to have partitions is to have have them as UBI volumes on top of MTD. UBI takes care ...
- 185
4
votes
0
answers
214
views
Missing space on root partition
I know, there are dozens of similar questions everywhere. I have looked at many of them, and checked what their answers suggested, to no avail.
My root partition (btrfs) is almost full according to df:...
- 140
4
votes
1
answer
487
views
Is there a way to monitor progress of a btrfs resize?
I'm shrinking a large btrfs partition using btrfs filesystem resize -xxxx /mountpoint.
The resize progress is really slow, is there anything like a progress bar?
- 141
4
votes
0
answers
339
views
Is it safe to enable Direct I/O for a loop device backed by a sparse file?
I'd like to have a sparse file, and mount it as a filesystem. It'd be great if the performance overhead is negligible, but only if that doesn't come with a data-loss risk! Is it safe to mount the ...
- 141
4
votes
0
answers
3k
views
btrfs trying to recover filesystem - bad tree block
I'm hoping someone can help me, trying to recover a btrfs pool, that lost 1st drive. I tried to mount the 2nd drive and I've been having fs errors.
I got the 1st drive readable again, but it appears ...
- 141
4
votes
0
answers
71
views
Why doesn't disk io occur to read file system metadata despite clearing dentry and inode with drop_cache command?
As the title says, I am confused about "echo # > /proc/sys/vm/drop_caches" and blockdev --flushbufs.
http://pages.cs.wisc.edu/~remzi/OSTEP/file-implementation.pdf
According to OSSTEP, If the ...
- 41
4
votes
2
answers
652
views
Make one program use a special resolv.conf
I want to cheat a program to use a special /etc/resolv.conf file, that in turn will force it to use a nonstandard nameserver.
The obvious solution is to recreate the whole filesystem except one file ...
- 201
4
votes
0
answers
560
views
moving a file from ntfs to btrfs while preserving the creation time
Both ntfs and btrfs support file creation times. When I copy a file however, only the modification time is preserved.
Is there a way to preserve creation times too?
For context I wish to migrate my ...
- 723
4
votes
0
answers
2k
views
processes hanging when trying to access a file
I'm running Ubuntu 16.04.5 and the ext4 filesystem, and I have a file which causes processes to hang when they read it.
For example:
$ cat /path/to/file.txt
and then from a separate terminal:
$ ...
- 151
4
votes
1
answer
2k
views
How can I re-partition a hard/ssd-drive without losing data?
When I got my notebook with a 512GB SSD, I reformatted it and installed Ubuntu. I've followed Ubuntu's suggestion to partition the drive, so I have it partitioned as follows:
$ sudo parted -l
Model: ...
4
votes
0
answers
742
views
Which filesystem will give me the best performance for both writing and reading small files?
My company developed an application that picks up (watches for) xml files of <10kb in size from a directory, reads it in sends the body as an api call to an external service and then moves the ...
- 141
4
votes
0
answers
393
views
Do the filesystem under Linux enforce serialization, which means only one change to the filesystem actually happens at any given time?
https://unix.stackexchange.com/a/12818/674
says
Lock files are used by programs to ensure two (well-behaved) separate
instances of a program, which may be running concurrently on one
system, ...
- 100k
4
votes
0
answers
1k
views
Stress testing storage media -- file vs block?
While looking for ways to stress an SDcard, I've noticed there are two ways one can approach this. One is to stress it by reading/writing blocks directly to the device file.
For example:
sudo ...
- 5,805
4
votes
0
answers
3k
views
How to interpret fdisk output?
How does one interpret fdisk -l output. I've included a sample output based on an image with my "best guesses", and then show the output based on the device which was used to create the image. ...
- 1,887
4
votes
0
answers
278
views
How to repair btrfs after broken sata cable?
A few days ago my btrfs raid56 filesystem was suddenly mounted read-only. Smartctl -all returned nothing but an error for one of the disks and after replacing the sata-cable the disk now shows its ...
- 41
4
votes
0
answers
3k
views
Difference in space reserved for inodes in ext4 and XFS partitions
I am formatting a couple of 60G Logical Volumes (vg01-logs and vg01-monitoring) in one of our servers. These partitions will hold a large number of small files, so I want them with more than the ...
- 5,014
4
votes
0
answers
2k
views
FUSE Overlay filesystem for "too long filenames"
Is there FUSE overlay filesystem, that:
* resolve on it's own "too long filenames" for underlying filesystem
* otherwise (for filenames fitting into limits of underlying filesystem) just proxy 1:1
?
...
4
votes
0
answers
621
views
Replacing a running binary on read-only file system
I have a simple updater bash script, which replaces files by removing the incident old files and copying new files from an archive to the running embedded target root file system. This way, the script ...
- 181
4
votes
0
answers
1k
views
Mount LVM volume as external usb drive? CentOS 6
I'm trying to mount my old 2x500GB drives to the new server which has the same drive volume. Both have LVM structure but it's not working.
root@server [/mnt/usb]# ls /dev/sd*
/dev/sda /dev/sda2 /...
- 129
4
votes
0
answers
506
views
shared filesystem with offline access
I would like a shared filesystem with offline access. I have two machines. One is a light laptop with a small amount of SSD storage that I carry with me. The other is a stay-at-home computer with much ...
- 995
4
votes
0
answers
340
views
How does fsnotify setting affect system performance?
Occasionally a software package I install complains that the default fsnotify setting is far too low for decent performance. Intellij IDEA or crashplan are two examples.
They suggest using fsnotify ...
- 1,115
4
votes
0
answers
2k
views
What options are there for tuning Linux file system caching?
What various types of caching are possible in the ext3 file system and how can their values be changed using system calls or other methods? I don't want to use commands or tools.
- 141
3
votes
0
answers
128
views
Unnormalized UTF-8 directory names
I noticed something interesting in one of my directories:
$ ls -li
total 36
2625309 drwxrwxr-x 2 dotancohen dotancohen 4096 Jul 4 2022 Español
2625385 drwxrwxr-x 2 dotancohen dotancohen 4096 Jul ...
- 15.7k
3
votes
0
answers
404
views
What is about dnode size and limits
I've copied a reddit post which asks my question and haven't been answered:
Greetings,
I've been tinkering with a tool to monitor ZFS usage and statistics for the last few weeks. It's encouraged me to ...
- 55
3
votes
2
answers
2k
views
Recommended scheme for partitioning root file system into subvolumes following the Filesystem Hierarchy Standard
The Filesystem Hierarchy Standard (FHS) is the formal codification for root file tree on Linux installations, as inherited from earlier iterations of Unix and POSIX, and subsequently adapted. It ...
- 330
3
votes
0
answers
590
views
Read-only file system, remounting in read-write mode leads to: Error opening file “/mnt/Samsung1/Untitled Document”: No such file or directory
I've dual boot Windows and using my Linux Mint's volumes messed with their file system.
After rebooting to Linux the external media drives were read-only.
After exhausting all the solutions on the web,...
- 31
3
votes
0
answers
1k
views
Backup entire zfs pool to different filesystem
I have a zpool with around 6TB of data on it (including snapshots for the child datasets). For the important data in it, I already have backups on filesystem level. As I need to perform some rather &...
- 31
3
votes
0
answers
51
views
How do I undo copying a file that is ended up in cache?
I have copied a large file to USB drive.
The file appeared to be copied almost instantly, but copying operation stalled at the very end. /proc/meminfo is showing large, gigabyte Dirty: entry which is ...
- 5,598
3
votes
0
answers
306
views
In f2fs (Flash-Friendly Filesystem) what is heap-based allocation?
When creating a new Flash-Friendly Filesystem (f2fs) with mkfs.f2fs, there is a switch to turn on or off what is described as "heap-based allocation". The man page describes the switch as:
...
- 197