I've 22Tb lun from SAN Storage (HITACHI) on my Linux Server(CentOS 6.7).
I configure multipath for this lun, and now I wanna remove it.
The storage team deattach the lun from my server and when I run "multipath -ll"it still exists.
mpathf (360060e801667af00000167af0000014b) dm-2 HITACHI,OPEN-V*12
size=22T features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=0 status=enabled
|- 3:0:0:3 sdf 8:80 failed faulty running
`- 3:0:1:3 sdn 8:208 failed faulty running
this message stay until I reboot the server and i can't reboot all of my servers because they are in production environment.
anybody know what should I do?
Thanks
First you need to be sure the mpathf device is not being used:
lsof | grep mpathf
dmsetup info mpathf | grep -i open
In the dmsetup info open count needs to be equal to 0
So you are using the luns with lvm or something else, you need to remove everything from the lun.
Now you can delete sub disks with echo 1 > /sys/block/<x>/device/delete
Related
I had a fully working Amazon Linux 2 instance, running on t2.small instance type. I wanted to try changing the instance to a t2.medium type to test. As I have done in the past, I simply shut down the instance, changed the type, and then restarted the instance.
After the restart, apache was down and my sites were un-reachable. I was able to login to the instance and when trying to start apache I discovered that the root drive was now read only which prevented start/etc. Through some troubleshooting I was able to get the drive remounted and thing running as normal, but everytime I restart the instance, it goes back to read-only and I have to perform the same fix each time to get it back to normal. I believe it's an issue with my /etc/fstab root device UUID not matching the current root device UUID. I never changed any of the attached EBS volumes, so I'm not sure how the change occured.
Some relevant info:
$ cat /etc/os-release
NAME="Amazon Linux"
VERSION="2"
ID="amzn"
ID_LIKE="centos rhel fedora"
VERSION_ID="2"
PRETTY_NAME="Amazon Linux 2"
ANSI_COLOR="0;33"
CPE_NAME="cpe:2.3:o:amazon:amazon_linux:2"
HOME_URL="https://amazonlinux.com/"
To discover the UUID mismatch/fix, I performed the following:
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda 202:0 0 50G 0 disk
└─xvda1 202:1 0 50G 0 part /
xvdb 202:16 0 50G 0 disk
xvdf 202:80 0 50G 0 disk
└─xvdf1 202:81 0 50G 0 part
$ sudo blkid
/dev/xvda1: LABEL="/" UUID="2a7884f1-a23b-49a0-8693-ae82c155e5af" TYPE="xfs" PARTLABEL="Linux" PARTUUID="4d1e3134-c9e4-456d-a253-374c91394e99"
/dev/xvdf1: LABEL="/" UUID="a8346192-0f62-444c-9cd0-655ed0d49a8b" TYPE="ext4" PARTLABEL="Linux" PARTUUID="2688b30d-29ef-424f-9196-05ec7e4a0d80"
I had read that a possible fix would be to perform the following:
$ sudo mount -o remount,rw /
mount: /: can't find UUID=-1a7884f1-a23b-49a0-8693-ae82c155e5af.
Obviously, that didn't work. So I looked at my /etc/fstab:
#
UUID=-1a7884f1-a23b-49a0-8693-ae82c155e5af / xfs defaults,noatime 1 1
/swapfile swap swap defaults 0 0
Seeing this mismatch, I tried:
sudo mount -o remount nouuid /
Which worked, made the root writeable and I was able to get services back up and running.
So, this is how I've come to the belief that it has to do with the mismatch of the UUID in fstab.
My Questions:
Should I change the entry in /etc/fstab to match the current UUID: 2a7884f1-a23b-49a0-8693-ae82c155e5af
Any idea why this happened and how I can prevent it from happening in the future?
I am trying to establish if there is an easier method to determine the WWID of an iSCSI LUN connected with a Linux Filesystem or mountpoint.
A frequent problem we have is where a user requests a disk expansion on a RHEL system with multiple iSCSI LUNs connected. A user will provide us with the path their LUN is mounted on, and from this we need to establish which LUN they are referring to so that we can make the increase as appropriate at the Storage side.
Currently we run df -h to get the Filesystem name, pvdisplay to get the VG Name and then multipath -v4 -ll | grep "^mpath" to get the WWID. This feels messy, long-winded and prone inconsistent interpretation.
Is there a more concise command we can run to determine the WWID of the device?
Here's one approach. The output format leaves something to be desired - it's more suited to eyeballs than programs.
lsblk understands the mapping of a mounted filesystem down through the LVM and multipath layers to the underlying block devices. In the output below, /dev/sdc is my iSCSI-attached LUN, attached via one path to the target. It contains the volume group vg1 and a logical volume lv1. /mnt/tmp is where I have the filesystem on the LV mounted.
$ sudo lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sdc 8:32 0 128M 0 disk
└─360a010a0b43e87ab1962194c4008dc35 253:4 0 128M 0 mpath
└─vg1-lv1 253:3 0 124M 0 lvm /mnt/tmp
At the 2nd level there is the SCSI WWN (360a010...), courtesy multipathd.
'uname -a' on my machine gives:
Linux ct-lt-966 4.9.0-8-amd64 #1 SMP Debian 4.9.144-3.1 (2019-02-19) x86_64 GNU/Linux
Currently the filesystem of my USB is MS-DOS 'FAT32' which has a ~4.5 GB maximum size for individual files. I want to change this filesystem to something else, which does not have a limit. (I am trying to put a 35GB file onto a 64GB USB but I believe most USB filesystems do not limit the size of individual files).
I have not found it clear what choices of USB filesystem that I have. I tried to change the filesystem to 'NTFS', but I could not install or locate 'mkfs.ntfs' or even 'ntfsprogs'. (I also tried installing with 'pacman' and 'yum' but apparently 'pacman' requires an aarch architecture and I could not get access to 'yum-config-manager' in order to enable any repos).
So to conclude, with my minimal prowess I am just looking for any way to change the filesystem of my 64GB USB to anything which will accept a 35GB file from my machine.
Thanks
Edit 1: Just planning to use the USB on this Linux machine, not Windows.
If there's nothing on the stick you want, or it's safe to delete it then basically:
delete the current FAT32 partition from the stick
add a new partition, utilising the full size of the device
create an ext4 filesystem on the new partition
PLEASE BE CAREFUL WITH THIS PROCESS: selecting the wrong device can obliterate a disk you needed such as a $HOME or your root OS
All the following is from memory and untested: I don't have a USB stick available right now to test fully.
Start by plugging in the stick while tailing the syslog in a console and see where it gets mounted (hopefully it automounts which it should if it's a desktop based Linux you're running. Possibly not if it's a server)..
sudo tail -f /var/log/syslog
(it might be /var/log/messages depending on distro)
then plug the stick. syslog should show it being allocated a device and a mount point. A file manager window may open depending on your config if you are in a GUI. For example, you might see it being loaded on /dev/sdc1 and mounted at /media/<yourusername>/USBKEY or something.
Confirm by running lsblk and note the device for the key, i.e.
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 167.7G 0 disk
├─sda1 8:1 0 69.9G 0 part /
└─sda2 8:2 0 97.9G 0 part /home
sdb 8:16 0 149.1G 0 disk
└─sdb1 8:17 0 149.1G 0 part /mnt/snapshots
sdc 8:32 0 931.5G 0 disk
└─sdc1 8:33 0 931.5G 0 part /storage
sdd 8:48 0 465.8G 0 disk
└─sdd1 8:49 0 465.8G 0 part /mnt/backup
sr0 11:0 1 1024M 0 rom
Unmount the stick (if it mounted) but leave it plugged in. Assuming again your device is at /dev/sdc1...
umount /dev/sdc1
Now run cfdisk in a terminal if you have it (friendlier) or fdisk if not, passing it the device related to your USB stick, without the partition number.
man cfdisk
sudo cfdisk /dev/sdc
This should show the current FAT32 partition. Delete it, then create a new partition of type 'Linux', following the defaults for start and end blocks which will be suggested in such a way as to fill the available space.
When done, select the option to Write the changes. Again, DOUBLE AND TRIPLE CHECK you have the right device or you will blow away your main disk probably.
Once the changes are written, you can create the ext4 file system;
sudo mkfs.ext4 /dev/sdc1
And after it completes, you should be able to re-plug your stick and find that it remounts, this time with a file system that can take your large files.
This isn't the only way to achieve this, but it's probably the least fiddly. For the sake of repetition, don't make a mistake with the device identifiers. If you're unsure, ask.
We have expend existing LUN size on EMC Storage and now i want to re-scan on Host side but i don't know how to figure out SCSI ID of that specific LUN. I am new to storage.. This is what i am doing but don't know whether it is a right way or not
Pseudo name=emcpowerj
CLARiiON ID=APM00112500570 [Oracle_Cluster]
Logical device ID=200601602E002900B6BCA114C9F8E011 [LUN01]
state=alive; policy=CLAROpt; priority=0; queued-IOs=0;
Owner: default=SP A, current=SP A Array failover mode: 1
==============================================================================
--------------- Host --------------- - Stor - -- I/O Path -- -- Stats ---
### HW Path I/O Paths Interf. Mode State Q-IOs Errors
==============================================================================
2 qla2xxx sdaj SP A1 active alive 0 1
2 qla2xxx sdaw SP B1 active alive 0 4
1 qla2xxx sdj SP A0 active alive 0 1
1 qla2xxx sdw SP B0 active alive 0 4
Here i am running find command on sdX device to find out SCSI ID to i can do echo 1 > /sys/bus/scsi/drivers/X:X:X:X/rescan to do re-scan LUN
$ find /sys/devices -name "*block*" | grep -e "sdaj" -e "sdaw" -e "sdj" -e "sdw"
/sys/devices/pci0000:00/0000:00:09.0/0000:05:00.1/host2/rport-2:0-1/target2:0:1/**2:0:1:8**/block:sdaw
/sys/devices/pci0000:00/0000:00:09.0/0000:05:00.1/host2/rport-2:0-0/target2:0:0/**2:0:0:8**/block:sdaj
/sys/devices/pci0000:00/0000:00:09.0/0000:05:00.0/host1/rport-1:0-1/target1:0:1/**1:0:1:8**/block:sdw
/sys/devices/pci0000:00/0000:00:09.0/0000:05:00.0/host1/rport-1:0-0/target1:0:0/**1:0:0:8**/block:sdj
or there is a alternative or other way to scan LUN?
I like to use the "lsscsi" program, which is probably available for your distribution.
% lsscsi
[0:0:0:0] cd/dvd NECVMWar VMware IDE CDR00 1.00 /dev/sr0
[2:0:0:0] disk VMware, VMware Virtual S 1.0 /dev/sda
[2:0:1:0] disk VMware, VMware Virtual S 1.0 /dev/sdb
As for rescanning the bus, that's pretty much it.
Rent a VPS (Ubuntu 12.04), have root access, however, don't see the device file /dev/mem.
Is there a way to create it to access bios info. Thanks.
mknod /dev/mem c `sed -n 's/ mem$//p' /proc/devices` 1