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Bug 997736 - virtio scsi disk could not be initialized when hotplug virtio scsi disk more than 995
Summary: virtio scsi disk could not be initialized when hotplug virtio scsi disk more ...
Keywords:
Status: CLOSED NOTABUG
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm
Version: 7.0
Hardware: x86_64
OS: Linux
medium
medium
Target Milestone: rc
: ---
Assignee: Asias He
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On: 841519
Blocks:
TreeView+ depends on / blocked
 
Reported: 2013-08-16 05:46 UTC by Xu Han
Modified: 2013-09-04 07:39 UTC (History)
17 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of: 841519
Environment:
Last Closed: 2013-09-04 07:39:21 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description Xu Han 2013-08-16 05:46:26 UTC 
+++ This bug was initially created as a clone of Bug #841519 +++

Description of problem:
 qemu monitor display "could not open disk image /home/disk/disk996.qcow2: Too many open files
 Property 'scsi-hd.drive' can't find value 'scsi996'
" when hotplug number more than 995.  not find any error message from syslog. host and guest work well. 

Version-Release number of selected component (if applicable):
#rpm -qa|grep qemu
qemu-kvm-1.5.2-3.el7.x86_64

# uname -r
3.10.0-8.el7.x86_64

guest: rhel7.0

How reproducible:
100%

Steps to Reproduce:
1./usr/libexec/qemu-kvm -enable-kvm -M pc-i440fx-rhel7.0.0 -smp 4 -m 3G -usb -device usb-tablet,id=input0 -name RHEL-Server-7.0-64 -drive file=/home/guest/scalability-RHEL7.0-64.qcow2,if=none,id=hd,format=qcow2,cache=none,werror=stop,rerror=stop -device virtio-scsi-pci,id=scsi0 -device scsi-hd,drive=hd,scsi-id=0,lun=0,id=scsi_image,bootindex=1 -netdev tap,script=/etc/qemu-ifup-switch,id=netdev0 -device virtio-net-pci,netdev=netdev0,id=device-net0 -spice port=5931,disable-ticketing -vga qxl -monitor stdio

2. hotplug virtio-scsi with this script
i=1
j=0
while [ $i -lt 16388 ]
do
    j=$((i%255))
    sleep 1 

    echo "drive_add localhost file=/home/disk/disk$i.qcow2,format=qcow2,media=disk,id=scsi$i,if=none" | nc -U /tmp/monitor2
    echo "device_add scsi-hd,bus=bus1.0,drive=scsi$i,scsi-id=$j,id=hd$i" |nc -U /tmp/monitor2

    i=$(($i+1))
done

3.check disks inside guest
(qemu) info block
  
Actual results:
(qemu) drive_add localhost file=/home/disk/disk995.qcow2,format=qcow2,media=disk,id=scsi995,if=none
OK
(qemu) QEMU 1.5.2 monitor - type 'help' for more information
(qemu) device_add scsi-hd,bus=bus1.0,drive=scsi995,scsi-id=230,id=hd995
(qemu) QEMU 1.5.2 monitor - type 'help' for more information
(qemu) drive_add localhost file=/home/disk/disk996.qcow2,format=qcow2,media=disk,id=scsi996,if=none
could not open disk image /home/disk/disk996.qcow2: Too many open files
(qemu) QEMU 1.5.2 monitor - type 'help' for more information
(qemu) device_add scsi-hd,bus=bus1.0,drive=scsi996,scsi-id=231,id=hd996
Property 'scsi-hd.drive' can't find value 'scsi996'

(qemu) info block
drive-virtio-disk1: removable=0 io-status=ok file=/home/guest/scalability-RHEL7.0-64.qcow2 ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0
ide1-cd0: removable=1 locked=0 tray-open=0 io-status=ok [not inserted]
floppy0: removable=1 locked=0 tray-open=0 [not inserted]
sd0: removable=1 locked=0 tray-open=0 [not inserted]
scsi1: removable=0 io-status=ok file=/home/disk/disk1.qcow2 ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0
scsi2: removable=0 io-status=ok file=/home/disk/disk2.qcow2 ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0
...
scsi994: removable=0 io-status=ok file=/home/disk/disk994.qcow2 ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0
scsi995: removable=0 io-status=ok file=/home/disk/disk995.qcow2 ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0


Expected results:
can hotplug 16384 virtio scsi disk.

Additional info:
Comment 2 Xu Han 2013-08-22 03:09:23 UTC 
Last week I just forgot to modify the limit on the number of open files.
Now, I have re-tested, and wouldn't hit this issue.
But in rhel7 guest, I find only 512 disks can be recognized, like weizhang hitted in Bug 841519, is it a problem?
Comment 3 Xu Han 2013-08-22 04:26:24 UTC 
Forgot to say, this time I bind all luns to one target, so the maximum lun number is 512?
Comment 4 Asias He 2013-09-04 04:46:31 UTC 
(In reply to xuhan from comment #3)
> Forgot to say, this time I bind all luns to one target, so the maximum lun
> number is 512?

We are supposed to support 2^14 == 16384 luns per target by virtio-scsi's design.
The largest luns per target I have ever seen is 512.

See: Bug 1000340 - linux guest can not support more than 512 luns per target
Comment 5 Xu Han 2013-09-04 07:39:21 UTC 
According to comment2. This is not bug.

QE will track bz1000340 as well.
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