virtualbox.org

Hello,

this problem arose some time ago (cannot recall, which version). But since the VM in question still works fine, i did not shout out. But after many release changes, i began to worry. This is what i can see:

The message appears 2 times (once for SATA2, once for SATA3)
On Sata3, there is an ISO, the disk comes up nicely and i can access the virtual CD just fine.
On Sata2 there is a vdi, that is immutable, meaning, that it gets reset before boot. It is where my swap space resides (swapfile.sys). That one also seems to work as expected.

That leaves me wondering, what may be the cause for the spurious messages emitted on a regular basis. Since the VM gets started by script (to set user/pwd via setcredentials), i also checked manualy booting, but same behavior.

I suppose, some dev could/should have a look into this. I am going to provide a log and a screenshot.
If i could/should add anything else, please notify.
Best regards
DdB

Could you please edit your message and replace the VBox.log with its ZIPPED counterpart, VBox.log.ZIP? You should know by now that this process saves a (virtual) tree!

00:00:02.208337 [/Devices/ahci/0/LUN#1/Config/Parent/Parent/Parent/Parent/Parent/] (level 10)
00:00:02.208338   Format <string>  = "VDI" (cb=4)
00:00:02.208339   Path   <string>  = "/mnt/data/vbox/VirtualBox VMs/Hauptmaschinen/Win7 lizensiert/Win7 lizensiert.vdi" (cb=81)

You should cut back on your snapshots. They tend to be maybe fragile and definitely lower performance if you stick too many on top of each other. You shouldn't be having more that 1 (one) snapshot, and that is mainly for "Undo" purposes. And it definitely doesn't help your "immutable" VDIs, you're just accumulating space on your host. Unused, wasted space.

00:00:02.335741 AHCI: LUN#0: CD/DVD
00:00:02.340624 AHCI: LUN#1: disk, PCHS=16383/16/63, total number of sectors 419430400
00:00:02.357410 AHCI: LUN#2: disk, PCHS=12483/16/63, total number of sectors 12582912
00:00:02.360314 AHCI: LUN#3: CD/DVD
00:00:02.360379 AHCI: Port4: No driver attached
00:00:02.360396 AHCI: Port5: No driver attached
00:00:02.360412 AHCI: Port6: No driver attached
00:00:02.360423 AHCI: Port7: No driver attached

You have extra ports in your SATA controllers, ports that are not used. Lower the "Port Count" in the VM settings « Storage » SATA controller to 4 (four), the number that you actually use. BTW, why do you have two CD/DVDs in your setup? Nothing bad, just out of curiosity...

DdB wrote:I suppose, some dev could/should have a look into this.

Not a developer. Do I count?

Hi socratis,

great work helpful insights. Thank you!

socratis wrote:Could you please edit your message and replace the VBox.log

done

socratis wrote:You should cut back on your snapshots. They tend to be maybe fragile and definitely lower performance if you stick too many on top of each other. You shouldn't be having more that 1 (one) snapshot, and that is mainly for "Undo" purposes. And it definitely doesn't help your "immutable" VDIs, you're just accumulating space on your host. Unused, wasted space.

Ouch. I am using snaps in very different ways, but made a strong habit of keeping at least 3 very relevant ones in order to be able to rollback depending on the mess i happen to experience. Many snaps are more like comments and do not really have data in their differing image. I am already in the process of moving the comments out to a logfile instead. But i think, i'll stick to using not just one but 3 different important snaps, integrating the earliest one only after creating #4 temporarily.

socratis wrote:You have extra ports in your SATA controllers, ports that are not used. Lower the "Port Count" in the VM settings « Storage » SATA controller to 4 (four), the number that you actually use.

WOW! That one made all the difference! And this setting really escaped my attention. The time, when i needed the additional disks temporarily is long gone!

socratis wrote: BTW, why do you have two CD/DVDs in your setup? Nothing bad, just out of curiosity...

ywc: one software, i use, needs the iso in the machine, the other drive is for convenience, if i have to put in guest additions for example. I am the only user of the VM, so it is really just for convenience of usage.

socratis wrote: Do I count?

sure you do
Thank you, looks like the problem is gone after decreasing the SATA count

DdB wrote:Thank you, looks like the problem is gone after decreasing the SATA count

Glad I could help. Marking as [Solved].

DdB wrote:made a strong habit of keeping at least 3 very relevant ones in order to be able to rollback

As long as you realize the potential issues, that's OK with me. As for the performance that I mentioned, you got to realize that VirtualBox needs to seek and read though the whole chain of the snapshots. Take a look at a *draft* about Snapshot basics and understand hopefully a little better how they work. And why they might be potentially fragile if one of the snapshot files gets corrupted (somehow).

PS. Thank you for replacing your log with its zipped counterpart!

socratis wrote:Glad I could help. Marking as [Solved].

done it myself now

socratis wrote:As long as you realize the potential issues, that's OK with me. As for the performance that I mentioned, you got to realize that VirtualBox needs to seek and read though the whole chain of the snapshots. Take a look at a *draft* about Snapshot basics and understand hopefully a little better how they work. And why they might be potentially fragile if one of the snapshot files gets corrupted (somehow).

Being aware that vbox snapshots and zfs snapshots, although the same name, are in fact very different. And i understand, how immutable devices pile up space in the snapshots. But there are advantages also! And those advantages are so strong IMHO that i moved most of my working environment into vm's. Even now, to access the forum, i have a dedicated vm for it. Performance has not yet troubled me too much, i am the only user on all vm's anyway.

Just an interesting observation: After knowing about this "fix", i noticed another vm, this time a linux vm, with the same message... and guess what: the amount of sata and sas connectors did not match the drive numbers. and after adjusting, the message went away.