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0
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0answers
27 views

access denied for folder in NFS share possibly for new users only. Why? [on hold]

On a one of our NFS filers, a user is unable to access the folders having group ownership and permissions. $ id -a uid=3234243(user1) gid=18027(sv_users) groups=18027(sv_users),18606(lts) $ls -ld /...
0
votes
1answer
42 views

storage performance test [closed]

So we have some operational Red-hat Linux on physical servers and company are we decided to migrate them to VM's. I wonder if they have same performance on writing and reading from disks. they are ...
13
votes
8answers
75k views

Finding all storage devices attached to a Linux machine

I have a need to find all of the writable storage devices attached to a given machine, whether or not they are mounted. The dopey way to do this would be to try every entry in /dev that corresponds ...
12
votes
2answers
6k views

How can I check the condition of an SD card?

How can I check the health condition of an SD card? When I want to check a hard drive, I can use SMART, how should I check an SD card? Is there a universal approach?
6
votes
1answer
4k views

Clear unused space with zeros (btrfs)

How to clear unused space with zeros ? (I am asking for tool for btrfs filesystem) I'm looking for something smarter than cat /dev/zero > /mnt/X/big_zero ; sync; rm /mnt/X/big_zero Like ...
1
vote
0answers
38 views

Difference between multipath -ll command and multipath -l command

From the multipath man page http://linux.die.net/man/8/multipath multipath -l shows the current multipath topology from information fetched in sysfs and the device mapper while multipath -ll shows ...
0
votes
1answer
20 views

List connected clients to an iscsi target

Is there any way to list the connected clients to an ISCSI target from another client. While sitting on the target itself , it may be easier to see which clients have mounted a particular target , ...
0
votes
0answers
50 views

Linux Mint installation showing entire Windows disk unallocated

I'm trying to install Linux Mint next to my install of Windows 10, but there's a problem. Mint is saying that the entire hard drive is unallocated "free space", though in the file explorer you can ...
2
votes
1answer
1k views

-bash: /usr/sbin/useradd: Input/output error — What does this mean?

Today, on my Centos server I tried to add a user but got the following error: -bash: /usr/sbin/useradd: Input/output error How do I fix it?
0
votes
3answers
75 views

Compress and remove original directory with limited storage

On my 3 TB external hard drive, I have a 2.7 TB directory containing relatively small files. I would like to compress this 2.7 TB directory and remove it to keep only the compressed version. The issue ...
1
vote
1answer
30 views

How to know what exactly is being written or which process is keeping my storage disk busy?

I have a server , which has gone rogue(not really), i ran nmon and saw that its Disk utilization is BAD, its 100% busy writing!! Here is the output : Can someone tell me what is keeping my disk ...
0
votes
1answer
41 views

How to deactivate linux page/disk cache?

I would like to turn off the disk / storage cache on Raspbian. I have done a serie of benchmarks on the microSD (http://jgp.net/microsd-card-performance-raspberry-pi/) but some people recommended I do ...
2
votes
4answers
62 views

Not enough disk space: remove first n lines of text file without copying the file [duplicate]

I want to remove the first $rmv lines of a huge text file called $filename. This text file is so big that I cannot fit two copies of it on my hard drive. The following leaves me with a blank file ...
0
votes
1answer
22 views

Azure Ubuntu Partition management

I'm working on an Azure Ubuntu VM root@dalil:/# df -h Filesystem Size Used Avail Use% Mounted on udev 1.7G 8.0K 1.7G 1% /dev tmpfs 345M 392K 344M 1% /run /dev/sda1 ...
0
votes
3answers
56 views

Why does reading a device require admin permissions?

I'm trying to create a backup script that saves my thumbdrive as an image. I'm planning on having it automatic. I've always seen the thumbdrive listed as /dev/sdb, and created a script that will save ...
0
votes
0answers
79 views

FreeNAS zpool not found

Consider me as new in FreeNAS storage. Disk failure on our FreeNAS 8.3 After rebuilding and replacing one disk on the RAID we are unable to access or mount the data. There are 8 X 3TB HDDs on the ...
1
vote
0answers
32 views

monitoring block access to disk

I am looking for a way to monitor access to disk blocks, and to monitor the access as a bitmap of blocks. I also need the capability to freeze (and queue) the device block access (and also to ...
2
votes
0answers
17 views

confused about dd write speed and VFS page cache

After reading some articles on the Linux VFS page cache and the tunable parameters like dirty_ratio i was under the impression that page cache would operate as both read and write caching layer. But ...
0
votes
1answer
53 views

Portable linux with disk-encryption: Which type of storage is better? SD-CARD or USB-STICK

So, as stated above, I mainly address some people, which may have made some experience with a portable os and various storage-types. As we know, the good old HDD are the most durable types of disks. ...
1
vote
0answers
75 views

bcache not working as expected with ramdisk as cache device

I was trying out bcache but i don't have an SSD so wanted to use free memory as a substitute. As ramdisk is listed in /proc/devices as block device i assumed this would work OK but with below simple ...
1
vote
1answer
99 views

Free and fast NAS software for arm

I own a bananapro computer and I wanna set up a NAS on it. I have already tried samba, but I don't like it very much. Is there alternative software for debian, that would work with Mac? Windows ...
4
votes
2answers
94 views

low remaining storage space, how do I increase it?

I keep getting low storage space warnings, I want to increase my total storage space, I was hoping to do that via terminal command, how would I go about doing that? I put in df -h and got: ...
1
vote
1answer
81 views

rsync generating a destination directory of bigger size than source?

We are copying our data from source server to destination server using rsync : rsync -av --progress --sparse user@destination server After rsync, we observed that destination directory is bigger in ...
1
vote
1answer
91 views

How replace disks on an existing striped zpool?

I have the following zpool: pool: mypool state: ONLINE scan: none requested config: NAME STATE READ WRITE CKSUM mypool ONLINE 0 ...
1
vote
1answer
481 views

Use “tune2fs” on XFS filesystem, get “Couldn't find valid filesystem superblock.”

I ran into this message two days ago=: tune2fs: Bad magic number in super-block while trying to open /dev/vdc1 Couldn't find valid filesystem superblock. The system is Ubuntu, a KVM virtual machine ...
1
vote
0answers
19 views

How much control do concrete file systems have over the VFS inode cache and the buffer cache?

I want to make sure I'm understanding how VFS inodes and file system inodes working together. A file system's inodes are stored on the block device and that is where they live. When an operation is ...
1
vote
0answers
54 views

FreeBSD 10.2 - Is three-way HAST replication possible?

I have a pair of FreeBSD 10.2 servers using HAST to keep a volume replicated between them. I'm introducing two new storage nodes that have much newer hardware and will eventually replace the existing ...
0
votes
2answers
46 views

What is Memory Technology Device?

Documentation and webpages are not very clear on this. Is it a Linux technology? Is it a type of storage device? Some other questions: If it is a Linux technology, what types of storage does it ...
34
votes
5answers
38k 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" ...
0
votes
3answers
207 views

df -h shows fs size smaller than LV size

I created a LV which it's size is 700MiB . When I mounted the FS, I noticed the df -h shows the filesystem's size is 697MiB. Where did 3MiB go? Could it reserved for the LVM's metadata? The FS is ...
1
vote
0answers
46 views

Are partition and volume the same concept?

From Silberschatz's Operating System Concepts A storage device can be used in its entirety for a file system. It can also be subdivided for finer-grained control. For example, a disk can be ...
0
votes
1answer
38 views

browse local S3 storage (not Amazon) with command line tool

I wish to browse, put and get files in local S3 storage from vendor EMC Atmos Cloud Storage I have a RHEL7 and wish to do it on command line. We have no flat structure (like Amazon) we use ...
0
votes
0answers
32 views

install redhat 6 without formating multipath disks

I've server RHEL 5 with multipath storage attached to it the OS is installed on local disks now I need to remove rhel 5 and install rhel 6 I perform fresh installation when i do this it shows me all ...
0
votes
0answers
17 views

How are the sizes of Linux directories determined? [duplicate]

The results of ls -lh provides, among other things, a listing of subdirectories and their sizes. As the directories' sizes are not determined by the sum of the files within them, how are they ...
8
votes
5answers
2k views

how do I wipe a server that I don't have physical access to?

I have a Godaddy dedicated server that I would like to cancel. Before I do that I'd like to do a clean format on the server to make sure that the next person who gets the server isn't able to undelete ...
0
votes
0answers
126 views

how can I see the uuid of a disk in my system WHEN IS NOT LISTED IN /dev/disk/by-uuid

I have a problem in my system, that I don't understand: there are no disks UUIDs, only partitions UUIDs: ls -al /dev/disk/by-uuid/ total 0 drwxrwxrwx 2 root root 140 Nov 21 20:36 ./ drwxrwxrwx 5 root ...
0
votes
2answers
690 views

How to benchmark memory in an embedded linux device?

Is there a generic utility to benchmark external memory device (eMMC, DDR) throughput on an embedded device (e.g. raspberry pi)? memtester, bonnie, bonnie++, memtest, dd? I've been running into ...
1
vote
0answers
34 views

Strange: Read Only FS

I am using LFS-based OS onto a 4GB storage device. Everything was working fine for more than 6 months. But suddenly, the storage device itself became Read-Only. No matter, what I do with this storage ...
3
votes
2answers
743 views

Parallel vs Distributed vs Traditional File system

I am trying to understand the differences between these three file system at a very basic level. Distributed FS: HDFS Parallel FS : Lustre Traditional FS : ext4/ext3/ NTFS/FAT etc. I want to ...
0
votes
1answer
35 views

Migrate to a new vdisk

I have to migrate some data to a new vdisk. But i have no idea how i can do this. The old Vdisk is under /dev/mapper/12345 which is a link to /dev/dm-1 The new Vdisk is under /dev/mapper/67890 which ...
2
votes
0answers
339 views

How do create an encrypted system with multiple Linux distributions?

A few weeks ago I created a completely encrypted system on a notebook and must say I like the idea. It's a little bit annoying to enter the password on every boot, but it's nice to know even if I lose ...
1
vote
0answers
84 views

Can't install EncFS

I have a 32GB SSD in my laptop and PCManFM 1.2.0 is showing 14.5GB free at the bottom right corner of the screen in the status bar. However, when I try to install an application such as encfs, I ...
0
votes
1answer
1k views

Mounting LUN in AIX

I have LUN created and added to AIX, I know this because once I created the LUN and the name I gave in the IBM storage is displayed and also I used the following commands chdev -l hdisk7 -a pv=yes ...
1
vote
2answers
327 views

Performance of `tar -xf` (block size related)

I'm recently working on optimizing the performance of tar -xf, i.e. untar a file. I notice that under default settings, tar -xf calls writes to write 10 KiB output at a time in chunks. However, this ...
45
votes
5answers
96k views

linux: How can I view all UUIDs for all available disks on my system?

My /etc/fstab contains this: # / was on /dev/sda1 during installation UUID=77d8da74-a690-481a-86d5-9beab5a8e842 / ext4 errors=remount-ro 0 1 There are several other disks on ...
0
votes
0answers
23 views

3 TB ext4 partition performance issue

I have deployed Centos 6.6 VM based on vSphere ESXi 5.5, it consists of 2 VMDK (virtual disks): 1st vmdk is for System / with 25 GB second vmdk /var is a 3TB / ext4 underlying storage is RAID 5 ...
11
votes
3answers
2k views

Ubuntu - No space left on device (NTFS)

I have a server which stores a lot of data, I keep many nested directories with millions of files in them. While trying to move one big directory (~700GB) from one disk to another I get an error: mv ...
12
votes
1answer
5k views

Defragmentation of LVM2 logical volumes

Question: Is there a tool supporting de-fragmentation of LVM2 logical volumes ? (Making their extents into consistent sequences) Preferably by defining desired order of extents (something like "...
1
vote
0answers
94 views

Unix (NFS Error)- 7320 Storage

I get the following errors on one of my servers: NFS op OP_OPEN got error NFS4ERR_DELAY causing recovery action NR_DELAY NFS op OP_WRITE got error NFS4ERR_STALE causing recovery action NR_STALE NFS4 ...
6
votes
1answer
107 views

How to restore an LVM container to a bigger physical partition?

The setup is an encrypted LVM container/PV that holds a few ext4 partitions. I am moving these to a new machine, but there is more room on the disk. So, I have created a bigger encrypted LVM ...