Hardware :: Red Hat (RHEL 5.6) Device Mapper Not Seeing LUN Changes?
Jun 23, 2011
Dell PowerEdge R610 with QLogic HBA card connected to HP EVA6000 SAN through a pair of switches.When I present space to the server, device mapper doesn't see it unless I restart the multipathd service. Same thing with unpresenting - the /dev/mapper/mpatha does not go away unless I restart multipathd.Here's what it looks like in 'multipath -ll' before and after I unpresent the LUN (without restarting multipathd)...
== BEFORE ==
# multipath -ll
mpathb (3600508b40010716b0000900001a40000) dm-8 HP,HSV200
Recently, I created a device sc0 through device mapper. The divice could be found in /dev/mapper/sc0. My problem is that the device doesn't exist in /dev/partitions which will block my following test.BTW, I found dm-0 in /dev/partitions. Is it the same as /dev/mapper/sc0? But the device /dev/dm-0 doesn't exist!
Slackware 13 Kernel 2.6.29.6 have three hard drives. Root is on own drive sda1. sdb and sdc are raid via mdadm with two partitions. one for /home raid0 md0 one for swap raid1 md1. md0 is encrypted vi cryptsetup. md1 is encrypted vi fstab. everything boots fine and is accessible. However, /dev/mapper/* shows sda1 as block device connected to the raid md0. swap crypted device is correct in /dev/mapper/*. fstab is set correctly. problem seems to be with initrd. I would like the correct device in /dev/mapper so that I can access drive info; size, available space, etc. now info shows only sda1 info
I am trying to prevent the dm_mod and friends from loading during install.I am installing by PXE boot with NFS and kickstart files over http. This works fine for other machines.Ok, I have a Dell PowerEdge 2900 III with 8gig ram, PERC 6/i raid controller.The raid has 8 1TB drives in it, so the total size of the device is >2TB.There is also an SATA drive, which is NOT on the raid controller.
The problem is, I want to install CentOS on the SATA drive. The SATA drive comes up as a device-mapper drive, with a big crazy device name.This is ok, but the problem is, when the system goes to boot, it just says 'missing operating system'.I can't boot from the raid because it is large enough to require a GPT partition, and CentOS says it can't boot from a GPT partition.The SATA drive would work FINE if I could just prevent the damn device mapper from loading, so that I could install on the SATA drive in ordinary SATA mode.
I have tried re-squashing the stage2.img with /etc/modprobe.conf with alias dm_mod off and such, no luck.I also tried adding an /etc/modprobe.d/blacklist file, that did not work either.I also tried putting blacklist= dm_mod in the kickstart file, but that seems to be a fedora-only option and it kills my install. any ideas on preventing the dm_mod et. al. from loading at install time??
Greetings Fellow Knights Of The Penguin Clan....!I am having issues with device mapper seeing a 275GB Raid5 Lun from my SAN storage.I'm using IBM 2145 San Volume Controller.I am able to see a 40 GB Raid 10 device though..
I have a linux machine, attached to a fibre channel SAN.
We're in the testing phases and we're attempting to get all of the bugs worked out before this goes live.
If i have my host streaming data to the storage device on the san (or from the device on the san) and simulate a path failure (by shutting down one of the host's ports on the FC switch), multipath does not pick up on another path until about 45 seconds have passed.
I can verify this by watching the statistic graph (which updates once per second) on the storage system.
I see iops running along rather nicely, and then they drop to 0 for 45 seconds, then pick right up to normal again.
This is a RehHat EL 5.5 system, with qlogic HBA's.
Am i being too picky? I'd expect multipath to recover in under 30 seconds, so as to not alarm host applications running on the linux host... 45 seconds seems like a long time to wait for a disk operation to complete.
Any tips on tuning Multipath, or the qlogic card? As it is, i've got the following options in my modprobe.conf.
Trying to do a yum update to get everything to latest, towards the end it says this:
[Code]...
how to get around this? I tried yum clean all, then yum update, again but it did the same. I had other deps missing on other servers but yum clean all fixed them -- can't find anyone else who's had this specific issue either, nor an rpm called 'device-mapper-event' or the other things that are missing - am kinda stuck!
I'm having some difficulities with truecrypt and cannot figure out what's wrong since this is my first attempt to create hidden encrypted partition. I'm using ubuntu 9.10 64b with latest 6.3a truecrypt. After using truecrypt gui (just command truecrypt) I've tried: create volume-->create volumne within a partition/drive-->hidden trucrypt volume --> select some /dev/sdX by my choice --> select aes & sha512 --> password --> and format it.
when formating finished message "wrong ss, swith or wrong superblock of /dev/loop0" appeared. I've got no idea what could I do with it neither know whats program trying to do! Ok formating's done, then if you're trying to mount that partition then I would expect prompt for password, but that did not happen ...
EDIT: sudo mount /dev/loop0 /media/tmp/ also complaint about wrong superblock, but that does not ring any bell since i've got no idea what /dev/loop0 is or is for...
Anyone know how device-mapper works, or can someone point me to any docco (other than the man page)?
Couple years ago I wrote a TrueCrypt wrapper script for use on Puppy Linux, and am reworking it for Ubuntu. Puppy sometimes didn't have the 'dmsetup' device-mapper utility available, but TrueCrypt still works without this when the '-m nokernelcrypto' option is used.
My script notices when dmsetup is available and skips this option. When the TC volume gets mounted (somehow using dmsetup), the Desktop icon is labled with the leaf name of the /media/mount_point -- so far, so good.
However, if I force the script to add the no-kernel-crypto option, and the TC volume is mounted without using dmsetup, the Desktop icon ls labled with the size of the volume. Say what?
Running df shows the difference between the two mounts is whether /dev/mapper is used. So *how is* dmsetup making this happen? The manpage isn't much help. Is it just the 'rename' sub-command? I am unable to find any details about this mechanism.
I run many 5.2 virtual machines inside of VMWare ESX3.5 I've updated a couple of test VMs from 5.2 to 5.3. The thing that stands out is that during boot time, the sequence gets to this stage:
device-mapper: dm-raid45: intialized v0.2429 Waiting for driver initialization.
Here it takes about 3 times longer than the previous Centos 5.2 (about 9 seconds instead of 3). Whereas inside a physical box the wait in 5.3 is the same as it was in 5.2
Installed Maverick last night... the system has been working fine all day... then on a reboot tonight got the following.
RAMDISK: gzip image found at block 0 usb 1-2: new high speed usb device using ehci_hcd and address 2 uncompression error VFS: Cannot open root device "mapper/mylaptop-root" or unknown-block(0,0)
[code]....
Then it gives the Kernel Panic
Kernel Panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0) Pid: 1, comm: swapper not tainted 2.6.35-22-generic #35-Ubuntu
Then a call trace...This is a brand new install of Maverick I copied my files onto a USB and did a fresh install on the whole drive using the alternate CD (the desktop and netbook editions both failed to read on my system) was previously using Karmic with no issues. I tried to e2fsck the dev/sda1 from the CD in "repair broken system" mode but the return was "clean" I read that as the file system being intact but this is an area that I have no real knowledge in.
i've just installed RHEL 6 with twm.i want to use mplayer but it can't open/initialize audio device. On the redhat homepage they said soundcard is auto-config'ed. i have 2 soundcards here buti compiled mplayer from source but it's the same.
Code: mplayer -ao help RET Available audio output drivers:
The Completely Fair Queuing (cfq) scheduler in Red Hat Enterprise Linux 5appears to have worse I/O read performance than in version 4. It appears as though the Completely Fair Queuing I/O scheduler (cfq) has a regression and thus exhibits reduced read-side throughput which can affect performance for both local and NFS mounted file systems.
One way to mitigate this is to set the cfq's slice_idle parameter to zero. To change this value, execute the following command echo 0 > slice_idle in the /sys/block directory appropriate for your situation, as shown below:
echo 0 > /sys/block/hda/queue/iosched/slice_idle
We are using NFS file systems in RHEL 5.3. I would like to know how to find which /dev/Device is being used by the NFS file systems, so that I could try setting the slice_idle to '0' to see if there is any difference in performance? In /etc/fstab I only see the actual NAS volumes for the NFS file systems.
I am using Centos 5.5. I have a luks partition that I can successfully open and mount manually. But the problem is upon boot up, the device is missing from /dev/mapper/device_name until I manually luksOpen it..then it appears as it has before. This makes it a problem for me to have it open and mounted automatically upon boot up. Why is the /dev/mapper/device_name missing untill I manually luksOpen it?
I am using CentOS 5.2. I am installing from disc on a machine with Intel Embedded Server Raid Technology. It has two 500 GB SATA drives. During the initial boot process, it sees that these two devices exist. However, after getting into the screen to partition and configure RAID, it just shows this:
Drive /dev/mapper/ddf1_MegaSR R! #0 (475879 MB) (Model: Linux device-mapper)
I want to do a RAID1 so that the disks are mirrored. However, I would expect to see both drives listed. I can select RAID to create RAID partitions, but I think I need to be able to see both drives in order to do this correctly.
im facing problem in mailserver which gives me insufficient space error, when i see details it showAug 3 12:10:02 3dserver zimbramon[17013]: 17013:crit: Disk warning: 3dserver.3dbp.in /dev/mapper/ddf1_3draidp1 at 93%how can i set the frequency on mail threshold warning which is at 10 minutes.
Well as you can see from my sig I am running Slack 13 and unfortunately did not discover the readme_crypt.txt on the installation cd until it was far too late. Not to worry, many hours burned and things learned.So I compiled and installed cryptsetup and for my test encryption I am using an external usb harddrive (sdb3).First off cryptsetup kept segfaulting with the luksFormat command and this seems to be a know bug. The workaround it to pass USE="dynamic" to config before you build the package. Then
We had this problem a while back but it went away with whatever updates lvm/cryptsetup have been through, but it's back again as of the latest update. Instead of symlinks to the /dev/dm-* devices, lvm and cryptsetup are both creating duplicate device nodes under /dev/mapper for already existing devices.
e.g. Code: gazl@slack:~$ ls -l /dev/mapper total 0 crw------- 1 root root 10, 61 Jan 23 16:48 control brw-rw-r-- 1 root disk 253, 0 Jan 23 16:48 lukssda5 brw-rw-r-- 1 root disk 253, 9 Jan 23 16:48 rootvg-lvhome
I am trying to setup a H/W RAID-1 matrix but I am unsuccessful. I am trying to get partitions installed as /dev/md0, /dev/md1 but it keeps going for /dev/mapper/isw...The reason is that I have R1Soft backup and it needs to hook the partitions as seen in /proc/partitions from /dev not /dev/mapper/isw. I have tried to boot the installation with various options but nothing!
I've encrypted the /home partition. I've been successful in doing this by following the instructions here:slackware64-current/README_CRYPT.TXTBut after upgrade to cryptsetup-1.2.0-x86_64, when I boot up I get 'no such file or directory while trying to open /dev/mapper/crypthome'I have to manually type 'cryptsetup luksOpen /dev/sda9 crypthome' and mount each time to get into the encrypted partition.I expect to be prompted for the password on boot but I just get that error, what is wrong?my config files:
is possible to edited the default RHEL CD to have it automatically install RHEL based off of a kickstart file that I will store locally on the CD. My plan would be to put a cd in a server and have the OS automatically being installed.
We are planning to migrate our LINUX server from RHEL 3to RHEL 5. What are the configuration difference between RHEL 3 to RHEL 5 for webserver installations?
I installed NFS and portmap for export a folder to another PC. /usr/local. ftp is server's hostname and ws01 is client's hostname. I edited file /etc/exports with next text: /usr/local ws01(rw,root_squash) *(ro)
I restarted service portmap and nfs. From client, I try check connection with server with command: showmount -e ftp and result is: mount clntudp_create: RPC: Port mapper failure - RPC: Unable to receive
I have 4 partitions in my system, out of which two(sda1, sda2) have windows on them. I have installed RHEL 4 32 - bit on sda3 and after that , installed installed RHEL 64-bit on to a partition sda 5. Now i am unable to boot into RHEL 32-bit. The error i am getting is Error 13: Invalid or unsupported executable format.
can not ping from host (RHEL 6) to RHEL 5 in (virtual)? I have stopped iptables on both machines. But still not able to ping from host machine to virtual.
I have RHEL 3 and Win XP Installed in my P.C?I want to uninstall RHEL 3 and install RHEL 9 without affecting XP.how can i do this and also where can i download free RHEL 9 version or any other latest linux distribution for free?
A client has sent me an RHEL 5.1 box for me to do some work on, but it's not registered with Red Hat. This is causing me problems, because it's a minimal installation, and I need some more dev software.My immediate reaction was to install various bits (emacs, and so on) from my Centos 5(.0) DVD.The base RHEL system only had one (disabled) repo entry,so I added a yum DVD repo entry in yum.conf.d.
This looked good to start with, but it doesn't work. Something in RHEL's pirut/yum/rpm/whatever is getting confused, and can't work out what is/isn't installed.
Question - how do you maintain an unregistered RHEL box? Has RH done something to make life difficult? Is my problem simply that I'm using a Centos 5.0 DVD, instead of Centos 5.1? Am I stuck with downloading lots of rpms from the net and doing everything manually? I really don't want to do that.
