Emulex LightPulse LPe1105-M4 HBA Przewodnik Instalacji Pobierz pdf (Strona 158)

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EMC Host Connectivity with Emulex FC HBAs and FCoE CNAs for the Linux Environment

Additional Notes

SuSE SLES 7 support a maximum of 128 SCSI devices as opposed to

the SuSE SLES 8 distribution, which supports all 256 SCSI devices.

The 256 total of SCSI devices includes any non-EMC storage array

devices, such as local disks.

Red Hat distributions

Red Hat Linux distributions can scan LUN numbers from 0 through

255; however, only the first 128 SCSI devices discovered by the

system will be mapped to an

sd device. Any gaps in devices

presented to the system will not result in gaps in the

sd device

names.

Note: The first device may be a non-zero LUN.

Examples:

◆ If you have allocated devices 0 through 255 to the Linux host, it

will be able to scan up to 255; however, only the first 128 devices

(0 through 127) will be usable and accessible by the host.

◆ If you have LUNs 128 through 255 assigned to a Linux host, you

will be able to scan through and use all of them.

◆ If you have LUNs 256 or above exported to a Linux host, the

Linux hosts will neither see nor be able to access those devices

with an address over 256.

In total, a Red Hat host could support disk devices from /dev/sda

through /dev/sddx.

SuSE distributions

For SuSE distributions prior to SLES 8, the limitations are the same as

for Red Hat distributions. SuSE SLES 8 is different in that it supports

up to 256 devices by default as it reserves 16 major numbers for SCSI

devices.

Each major number is allocated 0 to 255 minor numbers that are used

to denote the partitions for a SCSI device. Therefore, a product of 16

major numbers and 16 minor numbers yields up to 256 SCSI devices.

As a result, the kernel is able to scan logical devices ranging from 0

through 255. These disk devices would be reported as

/dev/sda

through

/dev/sdiu.

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Emulex LightPulse LPe1105-M4 HBA Przewodnik Instalacji Strona 158