Sponsored Content
Full Discussion: what is SAN
Top Forums UNIX for Dummies Questions & Answers what is SAN Post 52892 by Perderabo on Tuesday 29th of June 2004 08:30:15 AM
Old 06-29-2004
First think about disk arrays. A disk array might plug into a computer's scsi interface. The computer doesn't see the real disks. It sees make-believe disks provided by the array. You typically connect to a serial port on the disk array to program exactly what these disks look like. But to the computer, the disk seem like local disks. It can build a filesystem and mount it. Or it can use the raw disk space as with a database. You would usually mount the disk, but this is not absolutely required.

Next, instead of that scsi inteface, imagine a computer that talks to an attached disk array via fibre channel. We actually have several of these. You need fibre channel drivers on the computer. But no other special software.

Now unplug that fibre channel cable from the disk array and plug it into a SAN server. A SAN server is just a disk array on steroids....lots of steriods. Dozens of computers connect to it. You telnet into the SAN server to define what the make-believe disks look like but once again, to the computer they are just local disks.

SANs do have additional features beyond what a disk array can do to support clustering and backups, but to just get a handle on it, just think of it as a massive super disk array.
 

10 More Discussions You Might Find Interesting

1. AIX

San:

hi We have 2 AIX nodes running with HACMP and all of them connected to SAN, Our shared storage is shark; I need to create shared volume group and I need the HACMP take a ware of it. Regards (1 Reply)
Discussion started by: h2aix
1 Replies

2. Solaris

Thoughts/experiences of SAN attaching V880 to EMC SAN

Hi everyone, I wonder if I can canvas any opinions or thoughts (good or bad) on SAN attaching a SUN V880/490 to an EMC Clarion SAN? At the moment the 880 is using 12 internal FC-AL disks as a db server and seems to be doing a pretty good job. It is not I/O, CPU or Memory constrained and the... (2 Replies)
Discussion started by: si_linux
2 Replies

3. Solaris

Solaris and SAN

Hi, How can we differentiate a SAN disk with a Solaris local disk? Please respond. Thanks (4 Replies)
Discussion started by: balu_solaris
4 Replies

4. AIX

SAN error

Dera all I have error repeating for two day, when I checked the error log by errpt command: ------------------------------------------------------------------------ LABEL: SC_DISK_ERR2 IDENTIFIER: 79B0DF89 Date/Time: Wed Oct 31 02:41:36 SAUS Sequence Number: 9000... (1 Reply)
Discussion started by: magasem
1 Replies

5. Linux

Linux on SAN

Hello everyone. I was wondering if there is a way to increase the size on the LUN on a SAN and make the Linux kernel understand the changes without restarting? In the past it has always been rebooted to see the new values but im sure that there is a way now for the lvm to see the Free PE in... (8 Replies)
Discussion started by: d_ark
8 Replies

6. UNIX for Dummies Questions & Answers

Booting off of a SAN

Hello, I'm posting this in the "Unix for Dummies" forum, since it is more of a theoretical question than an exact problem/fix I'm inquiring about. I have a SunFire T2000 server with 4 internal hard drives, running Solaris 10. (So far so good :) The company just purchased a large EMC SAN. ... (5 Replies)
Discussion started by: FredSmith
5 Replies

7. AIX

New to San Storage

Can anyone recommend a good book on san storage basics and how it communicates with an AIX server? (1 Reply)
Discussion started by: NycUnxer
1 Replies

8. AIX

IBM SAN TO SAN Mirroring

Has anyone tried SAN to SAN mirroring on IBM DS SAN Storage. DS5020 mentions Enhanced Remote Mirror to multi-LUN applications I wonder if Oracle High availibility can be setup using Remote Mirror option of SAN ? (1 Reply)
Discussion started by: filosophizer
1 Replies

9. AIX

SAN Migration

Hi all, We are migrating our SAN storage from HSV360 to 3PAR. The system runs aix 6.1 version with HACMP. Please let me know what are requirements from OS side and how are the data copied to the new disks. (10 Replies)
Discussion started by: ElizabethPJ
10 Replies

10. Filesystems, Disks and Memory

Faster way: SAN hd to SAN hd copying

hi! i got a rhel 6.3 host that already have an xfs filesystem mounted from a SAN (let's call it SAN-1) whose size is 9TB. i will be receiving another SAN (let's call it SAN-2) storage of 15TB size. this new addition is physically on another SAN storage. SAN-1 is on a Pillar storage while the new... (6 Replies)
Discussion started by: rino19ny
6 Replies
voldiskadd(8)						      System Manager's Manual						     voldiskadd(8)

NAME
voldiskadd - Adds one or more disks for use with the Logical Storage Manager SYNOPSIS
/usr/sbin/voldiskadd disk-address-list DESCRIPTION
The voldiskadd utility sets up new disks that are added to the system after the initial system installation and configures the disks for use by the Logical Storage Manager. A valid disk label must exist on the disk before using the voldiskadd utility. One or more disks may be specified using a disk-address-list. Disk addresses in the list have the form dskn (for the entire disk) or dsknp (for a specific partition). When specifying multiple disks, use a space between entries. Disk address names relate directly to device names in the /dev/disk directory. For example, here are some valid voldiskadd disk-address-list specifications: # voldiskadd dsk1 # voldiskadd dsk2 dsk3a The file, /etc/vol/disks.exclude, may be used to exclude disks from use by voldiskadd. Each line of the file specifies the name of a disk to exclude (for example, dsk5). The voldiskadd utility prompts the user for a disk group name and disk media name for the disks. If a new disk group name is specified, that disk group is created for the new disks. If no disk group name is specified, the disks are left as unassigned replacement disks for future use. If an existing disk group name is specified, the user is prompted for whether the disks should be designated as spares for the disk group. If a disk is found to already contain non-Logical Storage Manager partitioning, the user is asked whether the disk should be encapsulated. Encapsulation turns each partition of the disk into a volume. A disk should be encapsulated if it contains file systems or data that should not be overwritten. If encapsulation is not desired for a disk, the disk can be initialized as a new disk for use by the Logical Storage Manager. For new disks, all space on the disk becomes free space in the disk's disk group. Context-sensitive help is available at every prompt by typing ?. Also, a list option can be used to get information on available target disks for an operation. The voldiskadd utility supports the following general classes of actions: Initializing a disk with reserved regions and partitions. Disk initialization is performed by calling voldisksetup command. Adding a disk to an existing disk group. This operation can be performed independently of the initialization of the disk drive to add a disk's storage space to a disk group's free space pool. The volassist command may subsequently allocate from that free space. The disk can also be added as a hot spare device. Creating new disk groups in which to import new disks. If no disk group exists for importing disks, the option of creating the disk group is offered. Encapsulating disks that have exist- ing contents. This is the default action for disks that do not have a valid, existing Logical Storage Manager private region, but that do have a disk label. Encapsulation is performed by calling volencap. Reconnecting a drive that was temporarily inaccessible. This situation is detected automatically, by noting that the specified drive has a disk ID that matches a disk media record with no currently associated physical disk. After reconnection, any stale plexes referring the disk are reattached, and any stopped volumes referring the disk are restarted. This reattach action is performed by calling the volrecover script. ERRORS
You may receive the following messages when using the voldiskadd command: Initialization of disk device special-device failed. Error: special-device or an overlapping partition is open. This message indicates that the partition you specified or an overlapping partition on the disk is actively in use. The partition could be a mounted UFS or AdvFS filesystem, initialized as an LSM disk or used as a swap device. special-device is marked in use for fstype in the disklabel. If you continue with the operation you can possibly destroy existing data. Would you like to continue?? [y,n,q,?] (default: n) This message indicates that the fstype of a partition or an overlapping partition is set in the disk label. The voldiskadd command prints this message to warn that a disk partition may have valid data which could be destroyed. If you are sure that the disk partition does not have valid data and that the partition can be added to LSM, you can ignore the warning message by entering y at the prompt. The voldiskadd command will proceed to initialize the disk partition and add it to LSM. FILES
A list of disks to exclude from use by voldiskadd. SEE ALSO
disklabel(8), volassist(8), voldisk(8), voldiskadm(8), voldisksetup(8), voldg(8), volintro(8) voldiskadd(8)
All times are GMT -4. The time now is 03:18 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy