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Questions tagged [unionfs]

UnionFS is a filesystem service for Unix-like operating systems that implements a stackable unification file system, which can appear to merge the contents of several directories, while keeping their physical content separate.

UnionFS is a service for , and which implements a stackable unification file system, which can appear to merge the contents of several directories (branches), while keeping their physical content separate. When mounting branches, the priority of one branch over the other is specified, so when both branches contain a file with the same name, one gets priority over the other.

Website: http://unionfs.filesystems.org

Wikipedia: http://en.wikipedia.org/wiki/UnionFS

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Any tricks for making sshfs authenticate only on write?

There is seemingly a trick for creating read-only sshfs logins with the read only attribute is enforced by the remote's ~/.ssh/authorized_keys file. You first create a program ~/.ssh/ro-sftp-server that runs sftp-server -R, which whatever other…
Jeff Burdges
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RAM disk and physical RAID

I need to create a lot of temporary files for which I need to have fast access, so I'm thinking about using a RAM disk. The problem is that the temporary files might get pretty big (1-4 GB) and in this case the disk-storage would be OK. Is there any…
quamis
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Custom initrd init script: how to create /dev/initctl

I have a virtual machine (VMM is Xen 3.3) equipped with two IDE HDD's (/dev/hda and /dev/hdb). The root file system is in /dev/hda1, where Scientific Linux 5.4 is installed. /dev/hdb contains an empty ext2 file system. I want to protect the root…
Posco Grubb
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AUFS: How to create a read/write branch of only part of a directory tree?

AuFS (another union file system) allows us to merge two trees into one, even when those trees overlap. We can then direct writes to the merged tree towards one of the branches and reads to another. The classic use of this is with a flash file system…
Jay M
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Is it possible to speed up network filesystem by sth like unionfs, aufs?

I need to speed up slow, large storage with local SSD drive. I figured out I could do this with union filesystems. Here are results with nginx reading data from: local SSD alone: ~140 transactions/s. large-slow storage alone: ~25…
Matt
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How to create a single directory using the free space of three servers?

For the sake of simplicity , is it possible to map somehow the free disk space on three servers into a single directory and have the filesystem handle the sharding? I believe https://github.com/trapexit/mergerfs might be it but I find the…
chx
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How can you unmount or unjoin a unionfs path?

I was able to set up a unionfs path but realized I wanted to change it. I can't seem to overwrite, unmount, or move the unionfs target directory. Is there a command that a non-root user (who set up the union) to change it? myuser@maven ~ $ unionfs…
Dan Mandle
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How to mount a root aufs in Red Hat / Fedora Core?

I'm trying to set up a virtual machine running Red Hat EL (actually Scientific Linux, but same difference) where the root file system is protected and not writable. I'd like to accomplish this with a union mount using aufs. That is, a writable file…
Posco Grubb
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Union multiple mounts to a single point, but keep them all read write

I've got over 1,000 directories, spread out over 6 servers. Technically they are home folders. It's guaranteed that there will never be any duplicate folder names. What I'd like to do is to mount them (NFS or SSHFS) to a 7th server and merge them…
Nick
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Is it possible to disable copy on write for AUFS?

I would like to set up a union mount with aufs such that new files can be created on a writable branch, but existing files cannot be modified. Is it possible to disable copy on write so that if an attempt is made to modify a file that already exists…
gregsymons
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