What happens to ESXi installed on SD card if it breaks?

[Ollfried]

Simple Question, simple answer? As far as I know ESXi will go on running, as it is completely loaded into memory, correct? Only configuratzion changes would be written to disk. What happens in that case? Is there a chance for a PSOD?

[alittle158]

Very minimal chance of PSOD.  ESXi will keep running until you reboot the host.

[Dave_Mishchenko]

I'd agree that you have a minimal chance of PSOD and for the most part it'll keep running.  http://paulgrevink.wordpress.com/2011/02/27/esxi-and-usb-failure/

Dave
VMware Communities User Moderator

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[idle-jam]

very rare and it will just keep running, if you have vmware ha then you do not need to worry much too ..

[jreininger]

Would it not matter based on the size of the USB stick?...

I just attedned the online 'Upgrading to ESXi 4.1' web 'class'.  They mentioned if a 1 GB USB is used when the host needs to page out it will page to a ram drive, which would be better in the case of  a failure, I'd think.  And the host ScratchConfig drive would be in system RAM, leaving less host RAM for the VMs.

But if a, I think, they said if a 4 GB or larger USB device is used, the ScratchConfig will page out to the USB device, which if you were paging (ie over-committing) the host.  It would then crash the whole host right?  No?

They r'cmd checking the following setting to ensure your scracthconfig was on the device and not in ram if using a 4 GB or larger USB boot device...

host > advanced settings > ScratchConfig > Scratchconfig.configuredScratchLocation

[DSTAVERT]

It doesn't matter how large the USB stick. ESXi will not use more than 1GB (slightly less actually). If running from flash you will want to create a scratch location a datastore although technically it is unnecessary for normal running.

[macpiano]

I'm wondering what do you to replace that card etc. if it does goes down?  I have 4 heavy duty vms running on SD cards and my vms has the storage on those drives as well. Is there a how to somewhere?

thanks

Gary

[DSTAVERT]

SD is not SSD. You can't run VMs on an SD flash drive. (the kind you put in your phone)

[macpiano]

I meant SSD like goes in the cameras. It's slot is built into the Dell R710. Pretty pretty cool. I do have 24 by 7 mission critical service with Dell that includes the vm card so I may let them fix it. lol

[DSTAVERT]

The card that goes into a camera is an SD card. You can't run VMs from that card. ESXi works well from those devices since ESXi runs directly into RAM. Very reliable devices. Again Not possible to run VMs on the card.

[macpiano]

Let me put it this way. It's the card that Dell puts in it servers to run VMware-off hand it's been over a year since I put the server in so I don't remember the flavor. What do you do if that card whatever you're calliing it gets hosed?

[alittle158]

Replace it with a fresh SD card preinstalled with ESXi (or install it yourself on a blank one), and restore the config from your backup.  Same process you would go through if you were using spinning media without RAID.

[macpiano]

To tell you the truth I need to backup all of these up. Where do I do that?

[Ollfried]

You can backup the whole configuration with rcli:

esxcfg-cfgbackup.pl --server <servername> -s <backupfile.cfg>