You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
194 lines
7.3 KiB
194 lines
7.3 KiB
This driver is for Compaq's SMART Array Controllers.
|
|
|
|
Supported Cards:
|
|
----------------
|
|
|
|
This driver is known to work with the following cards:
|
|
|
|
* SA 5300
|
|
* SA 5i
|
|
* SA 532
|
|
* SA 5312
|
|
* SA 641
|
|
* SA 642
|
|
* SA 6400
|
|
* SA 6400 U320 Expansion Module
|
|
* SA 6i
|
|
* SA P600
|
|
* SA P800
|
|
* SA E400
|
|
* SA P400i
|
|
* SA E200
|
|
* SA E200i
|
|
* SA E500
|
|
* SA P700m
|
|
* SA P212
|
|
* SA P410
|
|
* SA P410i
|
|
* SA P411
|
|
* SA P812
|
|
* SA P712m
|
|
* SA P711m
|
|
|
|
Detecting drive failures:
|
|
-------------------------
|
|
|
|
To get the status of logical volumes and to detect physical drive
|
|
failures, you can use the cciss_vol_status program found here:
|
|
http://cciss.sourceforge.net/#cciss_utils
|
|
|
|
Device Naming:
|
|
--------------
|
|
|
|
If nodes are not already created in the /dev/cciss directory, run as root:
|
|
|
|
# cd /dev
|
|
# ./MAKEDEV cciss
|
|
|
|
You need some entries in /dev for the cciss device. The MAKEDEV script
|
|
can make device nodes for you automatically. Currently the device setup
|
|
is as follows:
|
|
|
|
Major numbers:
|
|
104 cciss0
|
|
105 cciss1
|
|
106 cciss2
|
|
105 cciss3
|
|
108 cciss4
|
|
109 cciss5
|
|
110 cciss6
|
|
111 cciss7
|
|
|
|
Minor numbers:
|
|
b7 b6 b5 b4 b3 b2 b1 b0
|
|
|----+----| |----+----|
|
|
| |
|
|
| +-------- Partition ID (0=wholedev, 1-15 partition)
|
|
|
|
|
+-------------------- Logical Volume number
|
|
|
|
The device naming scheme is:
|
|
/dev/cciss/c0d0 Controller 0, disk 0, whole device
|
|
/dev/cciss/c0d0p1 Controller 0, disk 0, partition 1
|
|
/dev/cciss/c0d0p2 Controller 0, disk 0, partition 2
|
|
/dev/cciss/c0d0p3 Controller 0, disk 0, partition 3
|
|
|
|
/dev/cciss/c1d1 Controller 1, disk 1, whole device
|
|
/dev/cciss/c1d1p1 Controller 1, disk 1, partition 1
|
|
/dev/cciss/c1d1p2 Controller 1, disk 1, partition 2
|
|
/dev/cciss/c1d1p3 Controller 1, disk 1, partition 3
|
|
|
|
CCISS simple mode support
|
|
-------------------------
|
|
|
|
The "cciss_simple_mode=1" boot parameter may be used to prevent the driver
|
|
from putting the controller into "performant" mode. The difference is that
|
|
with simple mode, each command completion requires an interrupt, while with
|
|
"performant mode" (the default, and ordinarily better performing) it is
|
|
possible to have multiple command completions indicated by a single
|
|
interrupt.
|
|
|
|
SCSI tape drive and medium changer support
|
|
------------------------------------------
|
|
|
|
SCSI sequential access devices and medium changer devices are supported and
|
|
appropriate device nodes are automatically created. (e.g.
|
|
/dev/st0, /dev/st1, etc. See the "st" man page for more details.)
|
|
You must enable "SCSI tape drive support for Smart Array 5xxx" and
|
|
"SCSI support" in your kernel configuration to be able to use SCSI
|
|
tape drives with your Smart Array 5xxx controller.
|
|
|
|
Additionally, note that the driver will engage the SCSI core at init
|
|
time if any tape drives or medium changers are detected. The driver may
|
|
also be directed to dynamically engage the SCSI core via the /proc filesystem
|
|
entry which the "block" side of the driver creates as
|
|
/proc/driver/cciss/cciss* at runtime. This is best done via a script.
|
|
|
|
For example:
|
|
|
|
for x in /proc/driver/cciss/cciss[0-9]*
|
|
do
|
|
echo "engage scsi" > $x
|
|
done
|
|
|
|
Once the SCSI core is engaged by the driver, it cannot be disengaged
|
|
(except by unloading the driver, if it happens to be linked as a module.)
|
|
|
|
Note also that if no sequential access devices or medium changers are
|
|
detected, the SCSI core will not be engaged by the action of the above
|
|
script.
|
|
|
|
Hot plug support for SCSI tape drives
|
|
-------------------------------------
|
|
|
|
Hot plugging of SCSI tape drives is supported, with some caveats.
|
|
The cciss driver must be informed that changes to the SCSI bus
|
|
have been made. This may be done via the /proc filesystem.
|
|
For example:
|
|
|
|
echo "rescan" > /proc/scsi/cciss0/1
|
|
|
|
This causes the driver to query the adapter about changes to the
|
|
physical SCSI buses and/or fibre channel arbitrated loop and the
|
|
driver to make note of any new or removed sequential access devices
|
|
or medium changers. The driver will output messages indicating what
|
|
devices have been added or removed and the controller, bus, target and
|
|
lun used to address the device. It then notifies the SCSI mid layer
|
|
of these changes.
|
|
|
|
Note that the naming convention of the /proc filesystem entries
|
|
contains a number in addition to the driver name. (E.g. "cciss0"
|
|
instead of just "cciss" which you might expect.)
|
|
|
|
Note: ONLY sequential access devices and medium changers are presented
|
|
as SCSI devices to the SCSI mid layer by the cciss driver. Specifically,
|
|
physical SCSI disk drives are NOT presented to the SCSI mid layer. The
|
|
physical SCSI disk drives are controlled directly by the array controller
|
|
hardware and it is important to prevent the kernel from attempting to directly
|
|
access these devices too, as if the array controller were merely a SCSI
|
|
controller in the same way that we are allowing it to access SCSI tape drives.
|
|
|
|
SCSI error handling for tape drives and medium changers
|
|
-------------------------------------------------------
|
|
|
|
The linux SCSI mid layer provides an error handling protocol which
|
|
kicks into gear whenever a SCSI command fails to complete within a
|
|
certain amount of time (which can vary depending on the command).
|
|
The cciss driver participates in this protocol to some extent. The
|
|
normal protocol is a four step process. First the device is told
|
|
to abort the command. If that doesn't work, the device is reset.
|
|
If that doesn't work, the SCSI bus is reset. If that doesn't work
|
|
the host bus adapter is reset. Because the cciss driver is a block
|
|
driver as well as a SCSI driver and only the tape drives and medium
|
|
changers are presented to the SCSI mid layer, and unlike more
|
|
straightforward SCSI drivers, disk i/o continues through the block
|
|
side during the SCSI error recovery process, the cciss driver only
|
|
implements the first two of these actions, aborting the command, and
|
|
resetting the device. Additionally, most tape drives will not oblige
|
|
in aborting commands, and sometimes it appears they will not even
|
|
obey a reset command, though in most circumstances they will. In
|
|
the case that the command cannot be aborted and the device cannot be
|
|
reset, the device will be set offline.
|
|
|
|
In the event the error handling code is triggered and a tape drive is
|
|
successfully reset or the tardy command is successfully aborted, the
|
|
tape drive may still not allow i/o to continue until some command
|
|
is issued which positions the tape to a known position. Typically you
|
|
must rewind the tape (by issuing "mt -f /dev/st0 rewind" for example)
|
|
before i/o can proceed again to a tape drive which was reset.
|
|
|
|
There is a cciss_tape_cmds module parameter which can be used to make cciss
|
|
allocate more commands for use by tape drives. Ordinarily only a few commands
|
|
(6) are allocated for tape drives because tape drives are slow and
|
|
infrequently used and the primary purpose of Smart Array controllers is to
|
|
act as a RAID controller for disk drives, so the vast majority of commands
|
|
are allocated for disk devices. However, if you have more than a few tape
|
|
drives attached to a smart array, the default number of commands may not be
|
|
enought (for example, if you have 8 tape drives, you could only rewind 6
|
|
at one time with the default number of commands.) The cciss_tape_cmds module
|
|
parameter allows more commands (up to 16 more) to be allocated for use by
|
|
tape drives. For example:
|
|
|
|
insmod cciss.ko cciss_tape_cmds=16
|
|
|
|
Or, as a kernel boot parameter passed in via grub: cciss.cciss_tape_cmds=8
|
|
|