04-12-2013
The kernel usually probes all devices at boot time and places all found into /dev (unless a, say, USB drive is plugged in and identified by e.g. dbus/hal/udev).
If not found in /dev, your device might have a problem.
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1. AIX
Hy
I have several logical volumes that are turned into raw devices used by Informix DB. I would like to add some more.
In /dev directory i see logical volumes as block files: lv_name1, lv_name2 ...
and
i see raw devices defined as character files:
rlv_name1, rlv_name2 ...
As i see,... (5 Replies)
Discussion started by: veccinho
5 Replies
2. UNIX for Advanced & Expert Users
Hello group,
Is it possible to use partition on a disk as a raw device? I have a LUN on a SAN which I would like to partition and use those partitions as raw device.
If it is feasable, how do I bind them to a device?
For example, say sdd has 3 partitions on it, sdd1, sdd2 and sdd3. Can I... (1 Reply)
Discussion started by: bfay
1 Replies
3. Solaris
Hi All ,
I would like to know the procedure for increasing shared volume space in sun cluster .
Currently the configuration is like these .
Main stripe
oradb1/d91 2 1 /dev/did/rdsk/d35s0 1 /dev/did/rdsk/d36s0 =Total 49 Gb
oradb1/d94 -p oradb1/d91 -o 88080480 -b 14680064 ==Total 7 GB... (4 Replies)
Discussion started by: sahil_shine
4 Replies
4. AIX
Please consider this a question about basics&best practices. On AIX 5.3 system, three raw physical volumes are defined from storage. While doing a read with command dd from the raw device, the speed rate is 250Mb/s.
Then, it gets complex when I define these three pv's to an lv of type raw. Doing... (4 Replies)
Discussion started by: royalliege
4 Replies
5. Solaris
Hi,
I am using Sun Solaris 10 (Sparc 64 bit),
I have a meta device /dev/dsk/emcpower26a mounting on /u01. I want to make this metadeice as raw device.
Need solaris command to remove file system and make it as raw device ?.
Is there any solaris command to check raw devices ?.
Thanks (1 Reply)
Discussion started by: zeeshan047
1 Replies
6. Solaris
Hi,
I need to create 4 zones.
I have an array with a RAID5 volume. I have exported 4 LUNS from the array. Now my host see the 4 LUNS as raw devices.
I am partitioning each LUN using format then mounting each slice on the global zone. Then I am using each slice as a file system for my non... (3 Replies)
Discussion started by: general_lee
3 Replies
7. Solaris
Hi,
I'm trying to find out how to see used space on RAW device.
I tried with prtvtoc -f RAWdevice but for 3 different device I'm getting the same FREE_SIZE which look a bit impossible.
root@zg8cscfb1> prtvtoc -f /dev/md/redodg/rdsk/d300
FREE_START=0 FREE_SIZE=20352 FREE_COUNT=1 FREE_PART=... (2 Replies)
Discussion started by: MarioT
2 Replies
8. Red Hat
Hi,
How to find the raw device/multipath details of the LUN used by the diskgroups of the database.
file system type -- ASM
Oracle -- 11.2.0.3.0
OS -- Linux
This is RAC database.
Regards,
Maddy (2 Replies)
Discussion started by: Maddy123
2 Replies
RAW(8) System Manager's Manual RAW(8)
NAME
raw - bind a Linux raw character device
SYNOPSIS
raw /dev/raw/raw<N> <major> <minor>
raw /dev/raw/raw<N> /dev/<blockdev>
raw -q /dev/raw/raw<N>
raw -qa
DESCRIPTION
raw is used to bind a Linux raw character device to a block device. Any block device may be used: at the time of binding, the device
driver does not even have to be accessible (it may be loaded on demand as a kernel module later).
raw is used in two modes: it either sets raw device bindings, or it queries existing bindings. When setting a raw device, /dev/raw/raw<N>
is the device name of an existing raw device node in the filesystem. The block device to which it is to be bound can be specified either
in terms of its major and minor device numbers, or as a path name /dev/<blockdev> to an existing block device file.
The bindings already in existence can be queried with the -q option, with is used either with a raw device filename to query that one
device, or with the -a option to query all bound raw devices.
Once bound to a block device, a raw device can be opened, read and written, just like the block device it is bound to. However, the raw
device does not behave exactly like the block device. In particular, access to the raw device bypasses the kernel's block buffer cache
entirely: all I/O is done directly to and from the address space of the process performing the I/O. If the underlying block device driver
can support DMA, then no data copying at all is required to complete the I/O.
Because raw I/O involves direct hardware access to a process's memory, a few extra restrictions must be observed. All I/Os must be cor-
rectly aligned in memory and on disk: they must start at a sector offset on disk, they must be an exact number of sectors long, and the
data buffer in virtual memory must also be aligned to a multiple of the sector size. The sector size is 512 bytes for most devices.
Use the /etc/sysconfig/rawdevices file to define the set of raw device mappings automatically created during the system startup sequence.
The format of the file is the same used in the command line with the exception that the "raw" command itself is omitted.
OPTIONS
-q Set query mode. raw will query an existing binding instead of setting a new one.
-a With -q , specifies that all bound raw devices should be queried.
-h provides a usage summary.
BUGS
The Linux dd (1) command does not currently align its buffers correctly, and so cannot be used on raw devices.
Raw I/O devices do not maintain cache coherency with the Linux block device buffer cache. If you use raw I/O to overwrite data already in
the buffer cache, the buffer cache will no longer correspond to the contents of the actual storage device underneath. This is deliberate,
but is regarded either a bug or a feature depending on who you ask!
AUTHOR
Stephen Tweedie (sct@redhat.com)
Version 0.1 Aug 1999 RAW(8)