CentOS - Nov 2015 - getting a CentOS6 VM on VMware ESXi platform to recognize a new disk device

Boris Epstein wrote:
>>
>> My turn for a dumb question: from not paying a lot of attention to this
>> thread, the answer isn't clear to me: has the *host* recognized the
>> disk? If not, the guest's not going to see it.
>
> IMO your question is not dumb at all. Unfortunately, I don't have an
> answer to it.
>
> All I know is, you reboot the VM and it all works as expected.
Ok, if rebooting the VM, and *only* the VM, fixes it in the VM, then the
host - the system the VM's running on - knows about the drive. You see
where I was going with that....

       mark

On Wed, Nov 4, 2015 at 1:57 PM, <m.roth at 5-cent.us> wrote:
> Boris Epstein wrote:
> >>
> >> My turn for a dumb question: from not paying a lot of attention to
this
> >> thread, the answer isn't clear to me: has the *host*
recognized the
> >> disk? If not, the guest's not going to see it.
> >
> > IMO your question is not dumb at all. Unfortunately, I don't have
an
> > answer to it.
> >
> > All I know is, you reboot the VM and it all works as expected.
>
> Ok, if rebooting the VM, and *only* the VM, fixes it in the VM, then the
> host - the system the VM's running on - knows about the drive. You see
> where I was going with that....
>
>        mark
>
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
>
Mark,

Absolutely, I see your point. This was the starting point - you add the
device on the ESXi server, you reboot the VM, the VM sees the device, no
problem. Now, I ask - do I have to reboot the VM? Logically I hope there
ought to be a way for me not to have to do that - but I have yet to figure
out how to get there.

Boris.

On 11/4/2015 11:36 AM, Boris Epstein wrote:
> Absolutely, I see your point. This was the starting point - you add the
> device on the ESXi server, you reboot the VM, the VM sees the device, no
> problem. Now, I ask - do I have to reboot the VM? Logically I hope there
> ought to be a way for me not to have to do that - but I have yet to figure
> out how to get there.
>
vmware esxi 5.5.0 (free, using vsphere client to manage), vm is minimal 
centos 7 64bit.   I added a 16gb vdisk and immediately see this in dmesg...

[155484.386792] vmw_pvscsi: msg type: 0x0 - MSG RING: 1/0 (5)
[155484.386796] vmw_pvscsi: msg: device added at scsi0:1:0
[155484.388250] scsi 0:0:1:0: Direct-Access     VMware   Virtual 
disk     1.0  PQ: 0 ANSI: 2
[155484.391275] sd 0:0:1:0: [sdb] 33554432 512-byte logical blocks: 
(17.1 GB/16.0 GiB)
[155484.391552] sd 0:0:1:0: [sdb] Write Protect is off
[155484.391556] sd 0:0:1:0: [sdb] Mode Sense: 61 00 00 00
[155484.391593] sd 0:0:1:0: [sdb] Cache data unavailable
[155484.391595] sd 0:0:1:0: [sdb] Assuming drive cache: write through
[155484.396148]  sdb: unknown partition table
[155484.396356] sd 0:0:1:0: [sdb] Attached SCSI disk

and lsblk shows...

# lsblk
NAME                      MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda                         8:0    0   32G  0 disk
....
sdb                         8:16   0   16G  0 disk
...

so I can immediately...

# mkfs.xfs /dev/sdb
meta-data=/dev/sdb               isize=256    agcount=4, agsize=1048576 blks
.....
# mount /dev/sdb /mnt
#

(normally, I'd partition and lvm it, this is just for demo)
I'm using a paravirtual scsi controller, and have previously installed 
open-vm-tools via yum.

I then umounted it, and in vsphere deleted the vdisk and dmesg 
immediately shows...

[155820.730477] vmw_pvscsi: msg type: 0x1 - MSG RING: 2/1 (5)
[155820.730481] vmw_pvscsi: msg: device removed at scsi0:1:0
[155820.754176] sd 0:0:0:0: Attached scsi generic sg0 type 0
[155820.754247] sr 2:0:0:0: Attached scsi generic sg1 type 5


I also did much the same with a CentOS 6.7 VM, also using a 'paravirtual 
SCSI' vm on the same esxi host, when I added the vdisk, it immediately 
shows...

# dmesg
.....
vmw_pvscsi: msg type: 0x0 - MSG RING: 1/0 (5)
vmw_pvscsi: msg: device added at scsi0:1:0
scsi 2:0:1:0: Direct-Access     VMware   Virtual disk     1.0  PQ: 0 ANSI: 2
sd 2:0:1:0: Attached scsi generic sg2 type 0
sd 2:0:1:0: [sdb] 33554432 512-byte logical blocks: (17.1 GB/16.0 GiB)
sd 2:0:1:0: [sdb] Write Protect is off
sd 2:0:1:0: [sdb] Mode Sense: 61 00 00 00
sd 2:0:1:0: [sdb] Cache data unavailable
sd 2:0:1:0: [sdb] Assuming drive cache: write through
sd 2:0:1:0: [sdb] Cache data unavailable
sd 2:0:1:0: [sdb] Assuming drive cache: write through
  sdb: unknown partition table
sd 2:0:1:0: [sdb] Cache data unavailable
sd 2:0:1:0: [sdb] Assuming drive cache: write through
sd 2:0:1:0: [sdb] Attached SCSI disk

# lsblk
NAME                               MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sr0                                 11:0    1 1024M  0 rom
sda                                  8:0    0   16G  0 disk
??sda1                               8:1    0  500M  0 part /boot
??sda2                               8:2    0 15.5G  0 part
   ??vg_svfisc6test5-lv_root (dm-0) 253:0    0  9.6G  0 lvm  /
   ??vg_svfisc6test5-lv_swap (dm-1) 253:1    0  5.9G  0 lvm  [SWAP]
sdb                                  8:16   0   16G  0 disk

and I note this VM is *not* running vmware tools

NEITHER of these two VMs required rebooting or any echo "- - -" 
 >/sys/scsi/.. stuffs.


-- 
john r pierce, recycling bits in santa cruz