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List of Unix commands. List of Unix commands. Comandos de Shell Unix. Fstab (Español) El archivo /etc/fstab es usado para definir cómo las particiones, distintos dispositivos de bloques o sistemas de archivos remotos deben ser montados e integrados en el sistema. El archivo es leído por la orden mount, a la cual le basta con encontrar cualquiera de los directorios o dispositivos indicados en el archivo para completar el valor del siguiente parámetro.

Al hacerlo, las opciones de montaje que se enumeran en fstab también se aplicarán. Ejemplo de archivo He aquí una muestra de archivo /etc/fstab, utilizando nombres descriptivos del kernel: /etc/fstab # <file system><dir><type><options><dump><pass> /dev/sda1 / ext4 defaults,noatime 0 1 /dev/sda2 none swap defaults 0 0 /dev/sda3 /home ext4 defaults,noatime 0 2 Definiciones de los campos El archivo /etc/fstab contiene los siguientes campos separados por un espacio o una tabulación: <file system> - Define la partición o dispositivo de almacenamiento para ser montado. Identificación de los sistemas de archivos $ lsblk -f Etiqueta tmpfs Uso. Fstab (Español) Dump(8) 4.7. Mounting and Unmounting File Systems. The file system is best visualized as a tree, rooted, as it were, at /.

/dev, /usr, and the other directories in the root directory are branches, which may have their own branches, such as /usr/local, and so on. There are various reasons to house some of these directories on separate file systems. /var contains the directories log/, spool/, and various types of temporary files, and as such, may get filled up.

Filling up the root file system is not a good idea, so splitting /var from / is often favorable. Another common reason to contain certain directory trees on other file systems is if they are to be housed on separate physical disks, or are separate virtual disks, such as Network File System mounts, described in Section 29.3, “Network File System (NFS)”, or CDROM drives. During the boot process (Chapter 13, The FreeBSD Booting Process), file systems listed in /etc/fstab are automatically mounted except for the entries containing noauto. Device mount-point fstype options dumpfreq passno -a -d. 18.4. USB Storage Devices. Contributed by Marc Fonvieille. Many external storage solutions, such as hard drives, USB thumbdrives, and CD and DVD burners, use the Universal Serial Bus (USB).

FreeBSD provides support for USB 1.x, 2.0, and 3.0 devices. Support for USB storage devices is built into the GENERIC kernel. For a custom kernel, be sure that the following lines are present in the kernel configuration file: FreeBSD uses the umass(4) driver which uses the SCSI subsystem to access USB storage devices. Since any USB device will be seen as a SCSI device by the system, if the USB device is a CD or DVD burner, do not include device atapicam in a custom kernel configuration file. The rest of this section demonstrates how to verify that a USB storage device is recognized by FreeBSD and how to configure the device so that it can be used. 18.4.1.

To test the USB configuration, plug in the USB device. The brand, device node (da0), speed, and size will differ according to the device. Warning: Note: vfs.usermount=1. Oracle Solaris Open Source Projects on ZFS Deduplication: To Dedupe or not to Dedupe... ...that is the question. Ever since the introduction of deduplication into ZFS, users have been divided into two camps: One side enthusiastically adopted deduplication as a way to save storage space, while the other remained skeptical, pointing out that dedupe has a cost, and that it may not be always the best option.

Let's look a little deeper into the benefits of ZFS deduplication as well as the cost, because ultimately it boils down to running a cost/benefit analysis of ZFS deduplication. It's that simple. ZFS Deduplication: What Value Do You Get? ZFS dedupe will discard any data block that is identical to an already written block, while keeping a reference so that it can always reproduce the same block when read. Before you decide to use deduplication, it's good to know what value you'll get out of it.

Test it with some real data. Now take your total amount of storage and divide it by the dedup ratio, then subtract the result from your total amount of storage. ZFS Dedupe: The Cost. Deduplication with SSD instead of RAM? | The FreeBSD Forums. ZFS and SSD FAQ. A few weeks ago, a reader asked me a couple of questions about SSDs and ZFS, hinting that this might be a good topic to write a blog post about. Sure enough, just last week, a couple of similar questions came up, this time from a customer and a colleague at work. Well, if that's not a sign from heaven, I don't know what is, so here's a collection of frequently asked questions about flash memory (also known as solid state disks, or SSDs) and ZFS, with answers and some useful links, and an index, too.

Index What Are SSDs? "SSD" stands for "Solid State Disk". In short: A disk that doesn't have any moving parts. Today, most SSDs are made using flash memory, but some SSDs use a combination of RAM and some form of battery back up to make them permanent. Are Flash Memory and SSDs the Same Thing? Technically, no: SSDs are a drive category, and flash memory are a memory technology. Are SSDs "Better" Than Traditional Hard Disks? Are All Flash Memory SSDs Equal or are there Different Variants? No.

Yes: ZFS Administration, Appendix A- Visualizing The ZFS Intent LOG (ZIL) Table of Contents Background While taking a walk around the city with the rest of the system administration team at work today (we have our daily "admin walk"), a discussion came up about asynchronous writes and the contents of the ZFS Intent Log. Previously, as shown in the Table of Contents, I blogged about the ZIL in great length. However, I didn't really discuss what the contents of the ZIL were, and to be honest, I didn't fully understand it myself. Thanks to Andrew Kuhnhausen, this was clarified. Let's start at the beginning. The ZIL Function The primary, and only function of the ZIL is to replay lost transactions in the event of a failure. . $ iozone -ao This will run a whole series of tests to see how your disks perform.

. # zpool iostat -v 1 This will clearly show you that when the ZIL resides on a SLOG, the SLOG devices are only written to. The ZIL should always be on non-volatile stable storage! Synchronous Writes without a SLOG This isn't ALWAYS the case, however. Asynchronous Writes. How-To: Set up a home file server using FreeNAS. In today's digital world we've all got data, and lots of it. Our libraries are also growing rapidly: where you used to get by setting aside a few bookshelves for your books, CDs, DVDs and VHS tapes, we now require untold server space to preserve our beloved media in digitized form.

We also want our data to be itinerant, or at least seem that way. That is, if you want to take a book or disc to another room of your abode, you pull it from the bookshelf and take it with you. Similarly, if you're working on a document upstairs on your desktop and you want to move to the den with your laptop, you'll need the proper infrastructure working in the background to enable that kind of wizardry. So, how can we create this "digital bookshelf? " What is FreeNAS you say? Here's what you'll need, hardware-wise: A 64-bit Intel or AMD processor. If you're one of those extremely cautious people who has to double check everything, here's a URL to the FreeNAS hardware requirements.

FreeNAS Installation 1. 2. Mounting a USB FAT32 formatted disk in FreeNAS 8. If you want to mount a FAT32-formatted (or presumably FAT as well) USB drive in your FreeNAS server, here’s how you do it in FreeNAS 8. First, view your console either using the servers display, or the web interface (Settings > Advanced > Show Console Message in the footer). Plugging in your device should display messages similar to the following: Feb 27 20:56:34 freenas kernel: ugen1.2: <JMicron> at usbus1 Feb 27 20:56:34 freenas kernel: umass1: <MSC Bulk-Only Transfer> on usbus1 Feb 27 20:56:34 freenas kernel: da1 at umass-sim1 bus 1 scbus7 target 0 lun 0 Feb 27 20:56:34 freenas kernel: da1: <Hitachi HTS547550A9E384 A50A> Fixed Direct Access SCSI-2 device Feb 27 20:56:34 freenas kernel: da1: 40.000MB/s transfers Feb 27 20:56:34 freenas kernel: da1: 476940MB (976773168 512 byte sectors: 255H 63S/T 60801C) From this, we know the device is /dev/da1.

Next, either open the web console or SSH, so we can see what the partitions are and mount it Now, we’ll see what the partition listings are. Filesystem full, help pls | FreeNAS Community. Simple howtos. Disk info | Boot | Disk usage | Opened files | Mount/remount | Mount SMB | Mount image | Burn ISO | Create image | Memory disk | Disk performance Permissions Change permission and ownership with chmod and chown. The default umask can be changed for all users in /etc/profile for Linux or /etc/login.conf for FreeBSD. The default umask is usually 022. 1 --x execute # Mode 764 = exec/read/write | read/write | read 2 -w- write # For: |-- Owner --| |- Group-| |Oth| 4 r-- read ugo=a u=user, g=group, o=others, a=everyone # chmod [OPTION] MODE[,MODE] FILE # MODE is of the form [ugoa]*([-+=]([rwxXst])) # chmod 640 /var/log/maillog # Restrict the log -rw-r----- # chmod u=rw,g=r,o= /var/log/maillog # Same as above # chmod -R o-r /home/* # Recursive remove other readable for all users # chmod u+s /path/to/prog # Set SUID bit on executable (know what you do!)

Disk information Boot FreeBSD To boot an old kernel if the new kernel doesn't boot, stop the boot at during the count down. Disk usage Linux Remount. Simple howtos. 18.4. USB Storage Devices. Simple howtos. 18.9. Memory Disks. Reorganized and enhanced by Marc Fonvieille. In addition to physical disks, FreeBSD also supports the creation and use of memory disks. One possible use for a memory disk is to access the contents of an ISO file system without the overhead of first burning it to a CD or DVD, then mounting the CD/DVD media.

In FreeBSD, the md(4) driver is used to provide support for memory disks. The GENERIC kernel includes this driver. Device md 18.9.1. To mount an existing file system image, use mdconfig to specify the name of the ISO file and a free unit number. . # mdconfig -f diskimage.iso -u 0# mount /dev/md0 /mnt If a unit number is not specified with -u, mdconfig will automatically allocate an unused memory device and output the name of the allocated unit, such as md4. When a memory disk is no longer in use, its resources should be released back to the system. . # umount /mnt# mdconfig -d -u 0 To determine if any memory disks are still attached to the system, type mdconfig -l. 18.9.2. Learn FreeNAS » FAQ. What is ZFS? ZFS is a file system designed by Sun Microsystems for the Solaris Operating System. ZFS is open-source software and has therefore also been ported to FreeBSD the OS behind FreeNAS.

A traditional file systems resides on single hard drive and if you want to use more than one hard drive they need to be combined either with RAID or with a volume manager. ZFS is different, all ZFS filesystems are built on top of virtual storage pools called zpools. A zpool is constructed of virtual devices, which are themselves constructed of physical hard drives (or indeed files or hard drive partitions). Hard drives within a virtual device may be configured in different ways, depending on needs and space available: non-redundantly (similar to RAID 0), as a mirror (RAID 1) of two or more devices, as a RAID-Z group of three or more devices (which is similar to RAID 5), or as a RAID-Z2 group of four or more devices (which is similar to RAID 6). You can find more technical details on ZFS at Wikipedia. How To mount ISO images in FreeBSD and Linux | Tips And Tricks | An ISO image is an archive file (disk image) of an optical disc using a conventional ISO (International Organization for Standardization) format.

ISO image files typically have a file extension of .ISO. The name "ISO" is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660. 1. Procedure to mount ISO images under Linux You can mount an ISO image via the loop device under Linux. It's possible to specify transfer functions using loop device. You must login as a root user, if not root user then switch to root user using following command: $ su - Create the mount point: # mkdir -p /mnt/cdrom Use mount command as follows to mount iso file called image.iso: # mount -o loop image.iso /mnt/cdrom Change directory to list files stored inside an ISO image: # cd /mnt/cdrom # ls -l To unmount the image use command: # umount /mnt/cdrom 2.

First you have to create virtual device, using this command: