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Questions tagged [device-mapper]

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39 views

sar -dp reports individual disks higher than their devicemapper logical volume

I am trying to figure out how sysstat is reporting the utilization of the device mapper logical volume, lower than the individual disks that make up the logical volume. I keep trying to do the math ...
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79 views

How to remap deleted LV on thin provisioning volume

I have a thin-provisioning storage, on top of which I created an LVM disk. I didn't know that I had to set issue_discards = 1 in lvm.conf in order to have my disks actually deleted when I run lvremove....
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16 views

Portably determine the next available block device in a Linux VM?

I'm trying to use the code from https://stackoverflow.com/questions/32844854/boto3-show-next-available-device-name-on-instance: def get_free_device_name(instance): all_device_names = ["/dev/xvd%s"...
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1answer
33 views

VMWare device mapper size smaller than parition size

I am trying to understand what is going on with my VMWare instance. I have had 50GB partition that I extended to 150GB and resized the partition. However, the partition still shows that it only has ...
0
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2answers
62 views

How do you specify how much disk space for each mount point on vsphere?

I created a vm via the vsphere web client. The ESX version is 6.5 and the vsphere version is also 6.5 Via the menu: create virtual machine Option 2f: customize hardware Virtual Hardware: New Hard ...
1
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1answer
85 views

How to modify the “dm-*” value?

As I command multipath -ll, the output show like this. ocr3 (149455400000000000000000001000000ca0200000d000000) dm-9 IET,VIRTUAL-DISK [size=980M][features=0][hwhandler=0] \_ round-robin 0 [prio=0][...
1
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1answer
172 views

Cannot create PV on /dev/dm-NN (/dev/dm-N works)

I'm unable to create PVs on Multipath-Volumes that are available at /dev/dm-NN where N~[0-9] but I can create them on single digit devices like /dev/dm-9: # pvcreate /dev/dm-6 Physical volume "/dev/...
1
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1answer
262 views

Why is dmsetup failing when I try to create a snapshot?

I would like to create a COW device for an existing block device using dmsetup. The block device is: # blockdev --getsz /dev/loop0 3534848 I am trying to use a 256M ramdisk as the backing store: # ...
0
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1answer
85 views

Seeing Multiple Partition for same LUN

Anyone knows why I am seeing multiple device for the same LUN?I checked with storage team they only exposed 360000970000196801239533036304532 for this server but why I am seeing these many partition(...
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0answers
2k views

cryptsetup cannot close mapped device

When I run: LANG=C cryptsetup --debug luksClose /dev/mapper/Pool-A it fails as follows: device-mapper: remove ioctl on Pool-A failed: Device or resource busy Device /dev/mapper/Pool-A is still ...
11
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2answers
5k views

kvm to vmware migration - lvm based guest + multipathing

What is recommended way of migrate from kvm to vmware in case of lvm based guest with multipathing? I found that similar questions were already asked few years ago: How to migrate KVM based VMs ...
7
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1answer
9k views

how to correctly 'extend' a linux device mapper partition?

I am missing some concept with linux disk management, I have free space on a single physical volume that I want to to extend an ext4 file-system with, which is a logical volume. I look at fdisk -l - ...
0
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1answer
487 views

duplicate entries /dev/mapper

The system is Fedora 23. This occurred after a system upgrade. The issue is duplicate entries in /dev/mapper. As seen by /dev/mapper each partition is represented twice. How can the device based names ...
1
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1answer
602 views

I/O scheduling on LVM on dm-crypt

I have the following setup: Stock Debian stable (Linux kernel 3.16.7) running on Dell PowerEdge R320 Two SATA hard drives in RAID1 on a PERC H310 Mini controller, visible as /dev/sda dm-crypt target ...
1
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1answer
382 views

using same LVM volume for devicemapper and a bind mounted volume

I'm running an Amazon EC2 machine with a 512GB EBS mount. My plan is to split the EBS into two parts - one to be used by Docker 1.11 for its images (via devicemapper) and another to be bind-mounted to ...
1
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0answers
411 views

Is it possible to extend the data device of an Thin Provision pool setted by device mapper?

TL;DR : How can I extend the Thin-Pool if I'm not using LVM but Device Mapper itself directly? Detailed version: As far as I know, when we create a thin-pool by dmsetup, we can set a ...
3
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2answers
1k views

multipath, device mapper, and disk i/o scheduler

We have two machines with a multi path SAS controller, each with 12 physical disks attached. We were looking into some I/O speed oddness, and noticed that on one machine, where /dev/mpath/mpath*p1 ...
4
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0answers
237 views

How to disable write barrier on docker thinpooldev?

My server has very low disk performance if write barrier is enabled. As it has a disk controller with battery for the cache it is safe to add the "nobarrier" option to /etc/fstab. This makes a huge ...
1
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0answers
153 views

dmcache - is removing cache device without suspending safe?

I'm using plain dmcache for SSD cache - unmount procedure goes this way: umount fs suspend cache device remove cache device close lvm close LUKS shutdown However sometimes dmsetup doesn't allow me ...
7
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4answers
25k views

is /dev/dm-1 a partition or a whole block device?

Is there a way to figure out if /dev/dm-1 is a block device partition or a whole block device? If /dev/dm-1 is a partition, is there a way to find out the path to the corresponding whole block device?
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0answers
618 views

Linux, dev-mapper: How to mount a folder with different options than parent folder

I'm using CentOS 7.1 with device-mapper, and /home mounted as /dev/mapper/centos-home on /home type xfs (rw,relatime,seclabel,attr2,inode64,noquota) I'd like to include in fstab an entry for ...
20
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1answer
2k views

Why higher await time for DM multipath device than underlying device?

We have a CentOS 6.4 based server attached to Hitachi HNAS 3080 storage and observed the kernel remount the filesystem in read-only mode: May 16 07:31:03 GNS3-SRV-CMP-001 kernel: [1259725.675814] ...
11
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3answers
4k views

Linux device-mapper maps LVM PV nested inside LV when taking snapshot

Which is really messing with my plan to back up this machine... I have a server which is a KVM hypervisor to several virtual machines. One of these is running Docker. It has its Docker volumes on /...
2
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1answer
2k views

How to rebuild a dmraid RAID10 array?

Q: How do I force a rebuild? The following describes the scenario. I've been experimenting with forcing a RAID10 to rebuild, so I could see what dmsetup status output should look like when a RAID is ...