LinuxQuestions.org - Questions about naming sata-disks

Hi,

Welcome to LQ!

Quote:

Originally Posted by jehojakim (Post 3688659)

Hi

I am wondering how the naming scheme om SATA-disks is made. At this moment, I have 4 SATA-slots on my MB, SATA1 trough SATA4. SATA1 has /dev/sda, SATA 4 has sdb.

/dev/sda is boot disk.

How is this naming scheme accomplished?

And, related to that, will it still boot from this disk if I attach the disk to another SATA-port on the MB?

One step further, if I set up a RAID-5 with four disks, will I get in trouble if for some reason I swap disks in the RAID-5 configuration?

Thanks for your answers, or for putting me on the track for further searching.

regards, jehojakim

Your boot device is set by selection with your 'BIOS'. Most current distributions use 'udev' to recognize devices for the kernel via defined rules.

Code:

 excertp from 'man udev';



udev - dynamic device management



DESCRIPTION

      udev provides a dynamic device directory containing only the files for

      actually present devices. It creates or removes device node files in

      the /dev directory, or it renames network interfaces.



      Usually udev runs as udevd(8) and receives uevents directly from the

      kernel if a device is added or removed from the system.



      If udev receives a device event, it matches its configured rules

      against the available device attributes provided in sysfs to identify

      the device. Rules that match may provide additional device information

      or specify a device node name and multiple symlink names and instruct

      udev to run additional programs as part of the device event handling.



CONFIGURATION

      udev configuration files are placed in /etc/udev/ and /lib/udev/. All

      empty lines, or lines beginning with '#' will be ignored.



  Configuration file

      udev expects its main configuration file at /etc/udev/udev.conf. It

      consists of a set of variables allowing the user to override default

      udev values. The following variables can be set:



      udev_root

          Specifies where to place the device nodes in the filesystem. The

          default value is /dev.



      udev_log

          The logging priority. Valid values are the numerical syslog

          priorities or their textual representations: err, info and debug.



  Rules files

      The udev rules are read from the files located in the default rules

      directory /lib/udev/rules.d/, the custom rules directory

      /etc/udev/rules.d/ and the temporary rules directory

      /dev/.udev/rules.d/. All rule files are sorted and processed in lexical

      order, regardless in which of these directories they live.



      Rule files are required to have a unique name, duplicate file names are

      ignored. Files in /etc/udev/rules.d/ have precedence over files with

      the same name in /lib/udev/rules.d/. This can be used to ignore a

      default rules file if needed.



      Every line in the rules file contains at least one key value pair.

      There are two kind of keys, match and assignment keys. If all match

      keys are matching against its value, the rule gets applied and the

      assign keys get the specified value assigned.



      A matching rule may specify the name of the device node, add a symlink

      pointing to the node, or run a specified program as part of the event

      handling. If no matching rule is found, the default device node name is

      used.

I suggest that you read the 'man udev'. You can also look at 'Linux Kernel in a Nutshell' to get some insight.

These links and others can be found at 'Slackware-Links' . More than just Slackware® links!