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Search found 9 results on 1 pages for 'unionfs'.

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  • Custom initrd init script: how to create /dev/initctl

    - by Posco Grubb
    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 file system from writes by the VM by using aufs (AnotherUnionFS) to layer a writable file system on top of the root file system. The changes to / will be written to the file system located on /dev/hdb. (Furthermore, outside the VM, the file backing the /dev/hda will also be set to read-only permissions, so the VMM should also prevent the VM from modifying at that level.) (The purpose of this setup: be able to corrupt a virtual machine using software-implemented fault injection but preserve the file system image in order to quickly reboot the VM to a fault-free state.) How do I get an initrd init script to do the necessary mounts to create the union file system? I've tried 2 approaches: I've tried modifying the nash script that mkinitrd creates, but I don't know what setuproot and switchroot do and how to make them use my aufs as the new root. Apparently, nobody else here knows either. (EDIT: I take that back.) I've tried building a LiveCD (using linux-live-6.3.0) and then modifying the Bash /linuxrc script from the generated initrd, and I got the mounts correct, but the final /sbin/init complains about /dev/initctl. Specifically, my /linuxrc mounts the aufs at /union. The last few lines of /linuxrc effectively do the following: cd /union mkdir -p mnt/live pivot_root . mnt/live exec sbin/chroot . sbin/init </dev/console >/dev/console 2>&1 When init starts, it outputs something like init: /dev/initctl: No such file or directory. What is supposed to create this FIFO? I found no such filename in the original linuxrc and liblinuxlive scripts. I tried creating it via "mkfifo /dev/initctl", but then init complained about a timeout opening or writing to the FIFO. Would appreciate any help or pointers. Thanks.

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  • How can I "shadow" the filesystem on Linux?

    - by happy_emi
    On a Linux environment sometimes I need to run a script as root which will add/modify serveral files on my fs. Basically I'd like to know exactly which files are modified and how WITHOUT opening the script and trying to guess the code. I was thinking about using something like unionfs: the main fs would be accessible in readonly mode and all changes are written on a file used as a partition and "mounted" in write mode. Are there other ways to achieve the same goal (i.e. other than unionfs)?

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  • How to NFSv4 share a ZFS file system on FreeBSD?

    - by Sandra
    Using FreeBSD 9, and created a ZFS file system like so zfs create tank/project1 zfs set sharenfs=on tank/project1 There are many howto's on setting up NFSv3 on FreeBSD on the net, but I can't find any one NFSv4 and when the NFS share is done with ZFS. E.g. this howto say I have to restart the (NFSv3) by nfsd -u -t -n 4, but I don't even have nfsd. When I do # echo /usr/ports/*/*nfs* /usr/ports/net-mgmt/nfsen /usr/ports/net/nfsshell /usr/ports/net/pcnfsd /usr/ports/net/unfs3 /usr/ports/sysutils/fusefs-chironfs /usr/ports/sysutils/fusefs-funionfs /usr/ports/sysutils/fusefs-unionfs # I don't see any NFSv4 servers, which I could install with pkg_add. Question How do I install and setup NFSv4, so I can mount the share from e.g. a Linux host?

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  • Is there a way to do something like LVM over NFS?

    - by warren
    I realize that since NFS is not block-level, LVM can't be used directly. However: is there a way to combine multiple NFS exports (from, say, 3 servers) into one mount point on a different server? Specifically, I'd like to be able to do this on RHEL 4 (or 5, and re-export the combined mount to my RHEL 4 server). expansion The reason I pegged lvm is that I want a bunch of exported mounts (servera:/mnt/export, serverb:/mnt/export, serverc:/mnt/export, etc) to all mount at /mnt/space so that my /mnt/space on this server (serverx) as one large filesystem. Yes, I know that re-exporting is generally a Bad Thing™ but thought it might work, if there was a way to accomplish this on a newer release as opposed to an older one From reading the unionfs docs, it appears that I can't use it over a remote connection - have I misread it? More accurately, since Union FS merges the contents of multiple branches, but makes them appear as one, it doesn't seem to go in reverse: I'm trying to mount a bunch of NFS points in a merged fashion, then write to them - not caring where data goes, a la LVM .

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  • Can MySQL use multiple data directories on different physical storage devices

    - by sirlark
    I am running MySQL with its data dir on a 128Gb SSD. I am dealing with large datasets (~20Gb) that are loaded and processed weekly, each stored in a separate DB for the purposes of time point comparisons. Putting all the data into a single database in unfeasible because the performance on such large databases is already a problem. However, I cannot keep more than 6 datasets on the SSD at a time. Right now I am manually dumping the oldest to much larger 2Tb spinning disk every week, and dropping the database to make space for the new one. But if I need one of the 'archived' databases (a semi regular occurrence) I have to drop a current one (after dumping), reload it, do what I need to, then reverse the results. Is there a way to configure MySQL to use multiple data directories, say one on the SSD and one on the 2Tb spinning disk, and 'merge' them transparently? If I could do this, then archiving would no longer mean "moved out of the database entirely", but instead would mean "moved onto the slow physical device". The time taken to do my queries on a spinning disk would be less than that taken to completely dump, drop, load, drop, reload two entire databases, so this is a win. I thought of using something like unionfs but I can't think of a way to control which database gets stored on which physical drive, because it works by merging on a directory level (from what I understand) so I'm still stuck with using multiple directories. Any help appreciated, thanks in advance

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  • Linux that restores itself on each reboot

    - by jettero
    I'm looking for methods and software to help create a variant of lubuntu that will restore itself to an install state and/or update on every boot. I'm thinking of doing things like putting the root filesystem on a squashfs and using unionfs and tmpfs to make root writable, but automagically restorable. I'm thinking of updating the squashfs with rsync. Perhaps there are other ways to approach the problem. Perhaps root needn't be writable at all. All thoughts welcome. The home dir would be writable in the usual way. The goal, if it matters, is a Linux that's simple to maintain from the home office, but that functions correctly for customers. We have some custom software that we wish for customers to be able to run trivially on equipment we provide. Ideally these devices would have a "restore to factory" function that would put it back the way we intended. If this is part of the normal boot cycle, so much the better. Why lubuntu? Personal preference for this application. It has a usable desktop, but doesn't take up much ram.

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  • Best available technology for layered disk cache in linux

    - by SpliFF
    I've just bought a 6-core Phenom with 16G of RAM. I use it primarily for compiling and video encoding (and occassional web/db). I'm finding all activities get disk-bound and I just can't keep all 6 cores fed. I'm buying an SSD raid to sit between the HDD and tmpfs. I want to setup a "layered" filesystem where reads are cached on tmpfs but writes safely go through to the SSD. I want files (or blocks) that haven't been read lately on the SSD to then be written back to a HDD using a compressed FS or block layer. So basically reads: - Check tmpfs - Check SSD - Check HD And writes: - Straight to SSD (for safety), then tmpfs (for speed) And periodically, or when space gets low: - Move least frequently accessed files down one layer. I've seen a few projects of interest. CacheFS, cachefsd, bcache seem pretty close but I'm having trouble determining which are practical. bcache seems a little risky (early adoption), cachefs seems tied to specific network filesystems. There are "union" projects unionfs and aufs that let you mount filesystems over each other (USB device over a DVD usually) but both are distributed as a patch and I get the impression this sort of "transparent" mounting was going to become a kernel feature rather than a FS. I know the kernel has a built-in disk cache but it doesn't seem to work well with compiling. I see a 20x speed improvement when I move my source files to tmpfs. I think it's because the standard buffers are dedicated to a specific process and compiling creates and destroys thousands of processes during a build (just guessing there). It looks like I really want those files precached. I've read tmpfs can use virtual memory. In that case is it practical to create a giant tmpfs with swap on the SSD? I don't need to boot off the resulting layered filesystem. I can load grub, kernel and initrd from elsewhere if needed. So that's the background. The question has several components I guess: Recommended FS and/or block layer for the SSD and compressed HDD. Recommended mkfs parameters (block size, options etc...) Recommended cache/mount technology to bind the layers transparently Required mount parameters Required kernel options / patches, etc..

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  • Is post-sudden-power-loss filesystem corruption on an SSD drive's ext3 partition "expected behavior"?

    - by Jeremy Friesner
    My company makes an embedded Debian Linux device that boots from an ext3 partition on an internal SSD drive. Because the device is an embedded "black box", it is usually shut down the rude way, by simply cutting power to the device via an external switch. This is normally okay, as ext3's journalling keeps things in order, so other than the occasional loss of part of a log file, things keep chugging along fine. However, we've recently seen a number of units where after a number of hard-power-cycles the ext3 partition starts to develop structural issues -- in particular, we run e2fsck on the ext3 partition and it finds a number of issues like those shown in the output listing at the bottom of this Question. Running e2fsck until it stops reporting errors (or reformatting the partition) clears the issues. My question is... what are the implications of seeing problems like this on an ext3/SSD system that has been subjected to lots of sudden/unexpected shutdowns? My feeling is that this might be a sign of a software or hardware problem in our system, since my understanding is that (barring a bug or hardware problem) ext3's journalling feature is supposed to prevent these sorts of filesystem-integrity errors. (Note: I understand that user-data is not journalled and so munged/missing/truncated user-files can happen; I'm specifically talking here about filesystem-metadata errors like those shown below) My co-worker, on the other hand, says that this is known/expected behavior because SSD controllers sometimes re-order write commands and that can cause the ext3 journal to get confused. In particular, he believes that even given normally functioning hardware and bug-free software, the ext3 journal only makes filesystem corruption less likely, not impossible, so we should not be surprised to see problems like this from time to time. Which of us is right? Embedded-PC-failsafe:~# ls Embedded-PC-failsafe:~# umount /mnt/unionfs Embedded-PC-failsafe:~# e2fsck /dev/sda3 e2fsck 1.41.3 (12-Oct-2008) embeddedrootwrite contains a file system with errors, check forced. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Invalid inode number for '.' in directory inode 46948. Fix<y>? yes Directory inode 46948, block 0, offset 12: directory corrupted Salvage<y>? yes Entry 'status_2012-11-26_14h13m41.csv' in /var/log/status_logs (46956) has deleted/unused inode 47075. Clear<y>? yes Entry 'status_2012-11-26_10h42m58.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47076. Clear<y>? yes Entry 'status_2012-11-26_11h29m41.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47080. Clear<y>? yes Entry 'status_2012-11-26_11h42m13.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47081. Clear<y>? yes Entry 'status_2012-11-26_12h07m17.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47083. Clear<y>? yes Entry 'status_2012-11-26_12h14m53.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47085. Clear<y>? yes Entry 'status_2012-11-26_15h06m49.csv' in /var/log/status_logs (46956) has deleted/unused inode 47088. Clear<y>? yes Entry 'status_2012-11-20_14h50m09.csv' in /var/log/status_logs (46956) has deleted/unused inode 47073. Clear<y>? yes Entry 'status_2012-11-20_14h55m32.csv' in /var/log/status_logs (46956) has deleted/unused inode 47074. Clear<y>? yes Entry 'status_2012-11-26_11h04m36.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47078. Clear<y>? yes Entry 'status_2012-11-26_11h54m45.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47082. Clear<y>? yes Entry 'status_2012-11-26_12h12m20.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47084. Clear<y>? yes Entry 'status_2012-11-26_12h33m52.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47086. Clear<y>? yes Entry 'status_2012-11-26_10h51m59.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47077. Clear<y>? yes Entry 'status_2012-11-26_11h17m09.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47079. Clear<y>? yes Entry 'status_2012-11-26_12h54m11.csv.gz' in /var/log/status_logs (46956) has deleted/unused inode 47087. Clear<y>? yes Pass 3: Checking directory connectivity '..' in /etc/network/run (46948) is <The NULL inode> (0), should be /etc/network (46953). Fix<y>? yes Couldn't fix parent of inode 46948: Couldn't find parent directory entry Pass 4: Checking reference counts Unattached inode 46945 Connect to /lost+found<y>? yes Inode 46945 ref count is 2, should be 1. Fix<y>? yes Inode 46953 ref count is 5, should be 4. Fix<y>? yes Pass 5: Checking group summary information Block bitmap differences: -(208264--208266) -(210062--210068) -(211343--211491) -(213241--213250) -(213344--213393) -213397 -(213457--213463) -(213516--213521) -(213628--213655) -(213683--213688) -(213709--213728) -(215265--215300) -(215346--215365) -(221541--221551) -(221696--221704) -227517 Fix<y>? yes Free blocks count wrong for group #6 (17247, counted=17611). Fix<y>? yes Free blocks count wrong (161691, counted=162055). Fix<y>? yes Inode bitmap differences: +(47089--47090) +47093 +47095 +(47097--47099) +(47101--47104) -(47219--47220) -47222 -47224 -47228 -47231 -(47347--47348) -47350 -47352 -47356 -47359 -(47457--47488) -47985 -47996 -(47999--48000) -48017 -(48027--48028) -(48030--48032) -48049 -(48059--48060) -(48062--48064) -48081 -(48091--48092) -(48094--48096) Fix<y>? yes Free inodes count wrong for group #6 (7608, counted=7624). Fix<y>? yes Free inodes count wrong (61919, counted=61935). Fix<y>? yes embeddedrootwrite: ***** FILE SYSTEM WAS MODIFIED ***** embeddedrootwrite: ********** WARNING: Filesystem still has errors ********** embeddedrootwrite: 657/62592 files (24.4% non-contiguous), 87882/249937 blocks Embedded-PC-failsafe:~# Embedded-PC-failsafe:~# e2fsck /dev/sda3 e2fsck 1.41.3 (12-Oct-2008) embeddedrootwrite contains a file system with errors, check forced. Pass 1: Checking inodes, blocks, and sizes Pass 2: Checking directory structure Directory entry for '.' in ... (46948) is big. Split<y>? yes Missing '..' in directory inode 46948. Fix<y>? yes Setting filetype for entry '..' in ... (46948) to 2. Pass 3: Checking directory connectivity '..' in /etc/network/run (46948) is <The NULL inode> (0), should be /etc/network (46953). Fix<y>? yes Pass 4: Checking reference counts Inode 2 ref count is 12, should be 13. Fix<y>? yes Pass 5: Checking group summary information embeddedrootwrite: ***** FILE SYSTEM WAS MODIFIED ***** embeddedrootwrite: 657/62592 files (24.4% non-contiguous), 87882/249937 blocks Embedded-PC-failsafe:~# Embedded-PC-failsafe:~# e2fsck /dev/sda3 e2fsck 1.41.3 (12-Oct-2008) embeddedrootwrite: clean, 657/62592 files, 87882/249937 blocks

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