Hp EVA Array iSCSI Connectivity Option Bedienungsanleitung PDF herunterladen (Seite 80)

NOTE:

These symbolic links exist regardless of the number of disk partitions. Opening the partition devices

results in an error if the partition does not actually exist on the disk.

• The s ymbolic link mt maps to the auto-rewind SCSI tape device node for the LUN /dev/st0,for

example. Additional links for mtl, mtm,andmta map to the other auto-rewind devices /dev/st0l,

/dev/st0m, /dev/st0a, regardless of whether these device nodes actually exist or could be

opened.

• The symbolic link mtn maps to the no-rewind SCSI tape device node, if any. For example, this LUN

maps to /dev/nst0. Additional links formtln, mtmn,andmtan map to the other no-rewind

devices such as /dev/nst0l, /dev/nst0m, /dev/nst0a, regardless of whether those device

nodes actually exist or could be opened.

• The symbolic link cd mapstotheSCSICD-ROMdevicenode,ifany,fortheLUN/dev/scd0

for example.

• The symbolic link generic ma ps to the SCSI generic device node, if any, for the LUN /dev/sg0.

Because the symlink creation process must open all of the SCSI device nodes in /dev in order to

determine which nodes map to iSCSI devices, you may see many modprobe messages logged to

syslog indicating that modprobe could not ﬁnd a driver for a particular combination of major and

minor numbers. This message can be ignored. The messages occur when Linux is unable to ﬁ ndadriver

to associate with a SCSI device node that the iSCSI daemon is o pening as par t of its symlink creation

process. To prevent these messages from occurring, remove the SCSI device nodes that do not contain

an associated high-level SCSI driver.

Target bindings

The iSCSI driver automatically maintains a bindings ﬁle, /var/iscsi/bindings.Thisﬁle contains

persistent bindings to ensure that the same iS C SI bus and target ID number are used for every iSCSI

sessionwithaparticulariSCSITargetName,evenwhenthedriverisrepeatedlyrestarted.

This feature ensures that the SCSI number in the device symlinks (described in

“Device names” on page 79) always map to the same iSCSI target.

NOTE:

Because of the way Linux dynamically a llocates SCSI device nodes as SCSI devices are found, the driver

does not and cannot ensure that any particular SCSI device node /dev/sda, for example, always maps

to the same iSCSI TargetName.Thesymlinks described in “Device names”onpage79are

intended to provide application and fstab ﬁle p ersistent device mapping and must be used instead of

direct references to particular SCSI device nodes.

If the bindings ﬁle grows too large, lines for targets that no longer exist may be manually removed

by editing the ﬁle. M anual editing should not be needed, however, since the driver ca n maintain up

to 65,535 differ ent bindings.

Moun

ting ﬁle systems

Beca

usetheLinuxbootprocessnormallymountsﬁle systems listed in /etc/fstab before the network is

conﬁgured, adding mount entries in iSCSI devices to /etc/fstab will not work. The iscsi-mountall

script manages the checking and mounting of devices listed in the ﬁle /etc/fstab.iscsi, which has

thesameformatas/etc/fstab. This script is automatically invoked by the iSCSI startup script.

NOTE:

If iSCSI sessions are unable to log in immediately due to network or authentication problem s, the

iscsi-mountall script can time out and fail to mount the ﬁle s ystems.

Setting up the iSCSI Initiator and storage

1 2 ... 75 76 77 78 79 80 81 82 83 84 85 ... 228 229

Kommentare zu diesen Handbüchern

Keine Kommentare

Hp EVA Array iSCSI Connectivity Option Bedienungsanleitung Seite 80

Kommentare zu diesen Handbüchern

Verwandte Produkte und Handbücher für Computerzubehör Hp EVA Array iSCSI Connectivity Option