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I'm trying to create an All-in-one box which consists of ESXi running from an USB stick. Inside of ESXi there will be a vm which has been given direct access to a RAID controller for sharing it's disks via ISCSI back to this underlying ESXi server and also to other ESXi servers on the network.

I'm following the guide posted here http://www.napp-it.org/doc/downloads/all-in-one.pdf.

I purchased a 32GB USB stick for the system and storage vm's data files. The system (ESXi) installs fine onto the stick but after installation there is no datastore and rescanning for one does not reveal one either so I cannot install the storage vm.

How to make USB thumbdrive space visible as a datastore to ESXi 4.1 U1?

Henno
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2 Answers2

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Can't be done sorry, as you say ESXi is happy to boot from a USB disk but won't allow a datastore to be created on one - nor should it, using one as such is an appalling idea.

In fact your question history has interested me since you joined, you seem to ask lots of unusual questions that give the impression you've not received any training or read any documentation for ESXi - is this the case? it's just that you're questions come over as rather amateur.

Chopper3
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  • If you're certain that there's no way to make a datastore out of thumbdrive's leftover space, I should contact the author about it. It is true that I am not certified by VMware nor any other company. I have managed to avoid reading any IT related books since I learned to use Google. For me, ESX(i) is just another product I must get up. This is not said to diss the trainings or reading documentations. It's just that I have always managed to get everything up and running myself. Lately I discovered SO which has turned out to be a good place to gather second opinions. – Henno May 02 '11 at 13:38
  • What concerns using USB thumbdrive as a datastore to be an appaling idea - I would agree that normally, yes, but wouldn't you agree that it's better to have those 2 extra SAS hard drives in the RAID10 (more spindles = more speed!) than to waste their precious space (1.2TB) and spindle count just to run the storage OS while it could be done with 70€ thumbdrive? – Henno May 02 '11 at 13:55
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    Do you have any idea on what the performance of a thumb drive is like? – Doug Luxem May 02 '11 at 14:28
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    @Henno, I've just had to let a team of 40 offshore IT guys 'go' because they could only get our test ESXi environment 'up and running', it fell over quite spectacularly at a massively inopportune moment costing my business a month's delay in bringing a >$200m project to market. Not one had gone on training to save themselves money and it showed, their environment was riddled with stupid ideas and assumptions such as not understanding the expensive storage and networking I'd bought them. Dismissing any form of training in such a complex and critical technology is deeply unprofessional. – Chopper3 May 02 '11 at 14:36
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    @Henno - and your obvious lack of understanding of both the performance and write-management characteristics of USB flash drives proves again that perhaps this site, which is for IT professionals, may not be for you - this site is about fixing server faults, not creating them. – Chopper3 May 02 '11 at 14:38
  • @Henno, just reading that document you link to, I can't see any reference to its writer suggesting you can run your VMs off USB flash anyway - have you misread it? – Chopper3 May 02 '11 at 14:53
  • @Doug, Yes I do. In fact, when I was buying the stick, I went through 3 different stores and bugged each one's clerk with insisting on bringing out the fastest ones they had and looking them up on usbflashspeed.com. I paid particularly close attention to write speed at 4KB as this is the usual block size. – Henno May 02 '11 at 14:58
  • Actually I already had a running Ubuntu on this system (4GB Apacher thumbdrive). That was before I discovered this article. Everything was running smoothly, aside from installing Ubuntu on the flash for half an hour and the fact that adding packages was way slower than on hard disk but it was usable. This ubuntu shared out RAID controller's virtual drives (150GB SSD array of 10 drives in RAID10 and 2.7GB SAS array of 10 drives in RAID10) via ISCSI. I just found an article where it was described how I could use the storage box itsef as a virtual machine host. – Henno May 02 '11 at 15:07
  • @Henno, was it a "DTU30/32GB" you bought? If so it's worth knowing that USB3 isn't supported by ESXi at all right now, also at 4KB/sector that's about 8.8MBps MAX read and 6MBps write you'd be getting, off a FAT/NTFS formatted version in a single-user mode, there's no support of ESXi. – Chopper3 May 02 '11 at 15:09
  • @Chopper3, the part which you missed is paragraph 7.1.1 (last sentence). – Henno May 02 '11 at 15:10
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    I have to agree with Chopper3 regarding where you're referencing using the flash drive. SSD != Flash drive. Save yourself the headache, put everything on a single RAID 10. Disk write performance for the hypervisor is pretty low key. – Holocryptic May 02 '11 at 15:10
  • @Henno, I don't think I did miss anything, I reread 7.1.1, where does it even vaguely hint at the ability to use a USB flash drive as a VMFS datastore? – Chopper3 May 02 '11 at 15:12
  • Perhaps then I missed something myself. The sentence that I was referring to is this: "ESXi needs about 4GB, ***but we will add a storage OS***, so ***it could be a 16-32 GB SLC-USB3 Stick*** connected to USB2 but best is any 50 GB Sata SSD" – Henno May 02 '11 at 15:14
  • @Holocryptic, How would I then be able to share this RAID10 to other ESX servers? – Henno May 02 '11 at 15:17
  • @Henno, is English your first language? I ask because your comprehension skills have failed you, the writer is saying you can boot from USB but given they want a storage OS you'd be best with a SATA disk - NOT that it'll work with the USB stick. – Chopper3 May 02 '11 at 15:18
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    @Henno except no where else in the document does it reference the USB stick. So if it's not in the document that you're trying to use, don't try to cram it in there. Just get an SSD, or run everything in a RAID-10. It sounds like you're trying to over engineer the wheel here. – Holocryptic May 02 '11 at 15:18
  • @Chopper, the socket is USB2 so ESX would not know about it anything. – Henno May 02 '11 at 15:19
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    @Henno, I think you're a troll trying to wind us up, if you are please stop as your unprofessional approach goes against what we stand for here. edit - and you don't think from a signalling perspective the drive might start up a little different to a regular USB2 port then? actually USB3 drives try for USB3 speeds/signals first only dropping to USB2 after no response. – Chopper3 May 02 '11 at 15:20
  • @Chopper, no English is not my first language perhaps this is indeed what got me off the track. FWIW though, the author is not native English speaker either. ;-) I'm absolutely not trying to wind you up. From my point of view, it is you who are trying to pull a sack over *my* head by saying that putting a raid passthrough vm's data files on a usb stick is unprofessional and that thankfully cannot be done. I'm just amazed that you say that. Have you guys even tried to install OS on a USB drive? I have and it works (as I described above). I will stop "trolling" and consult the author. – Henno May 02 '11 at 15:28
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    @Henno - I run ESXi 4.1u1 from SD in over a thousand hosts, I'm totally happy to run the base OS off flash because ESXi is designed to not write (heavily) back to its boot disk when it detects it's flash - what I'm saying is that running actual VMs off USB flash in anything but a temporary way is beyond stupid unless those VMs are specifically designed to run off slow, unreliable storage that they know not to write to. Again you've misunderstood what we're saying. – Chopper3 May 02 '11 at 15:33
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    @Henno - even if it "works", it's still a crap idea. The usefulness of USB thumb drives start and end in their ability to transfer files between systems via sneakernet. They have *no* place in server systems. They are built for temporary storage of non-critical data, nothing more. – EEAA May 02 '11 at 15:33
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    ...it would also "work" for me to put a $50 netgear unmanaged switch at the core of my network, but would that be a good idea? Don't think so. – EEAA May 02 '11 at 15:42
  • Do you think I want to use a USB thumbdrive as my primary datastore? This is not the case. Maybe the whole confusion has emerged from me not expressing myself clearly enough: I am not planning to run VMs (plural) off from the thumbdrive. I just need one little VM there which exposes the RAID10 hard drives via ISCSI. That VM is not doing anything else than just being a bridge between RAID controller and the network. Heck, to really spare the write cycles, I can even put it's /var directory on a ramdrive and set up logrotate to discard yesterdays logs but I think that's an overkill. – Henno May 02 '11 at 15:56
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    @Henno - still, as I said, a crap idea. You *are* running a VM off of the USB drive, and, oh, by the way, it's not just *any* VM, but one that many other things are dependent on. Save yourself many headaches down the road and just do it right. Forget about the USB thumbdrive idea. – EEAA May 02 '11 at 16:11
  • ...or I can just cut two 600GB drives from my RAID10 SAS array and install the 3GB ESXi there. I was just hoping to save 1196GB of precious SAS disk space, 2 spindles and 2 bays. – Henno May 02 '11 at 16:19
  • @Henno I'm a bit confused anyways. You say you're following the guide here. You'd be connecting a HDD directly to a SATA connect directly on the MOBO, presumably, and have the storage attached to the PCI controller. I don't see what the big deal is. – Holocryptic May 02 '11 at 17:13
  • @Holocryptic, The guide says (my interpretation anyways) that it should be ok to install either to 16-32GB stick or 50GB sata ssd. I don't have any room in that 2U chassis for an internal sata drive (http://bit.ly/exvRrj) so I had to stick with the stick. The bays house 12 SSD drives and 12 SAS drives. I really don't want to touch them. But the consensus here seems that even if it would be possible to put storage vm files to a stick it would be stupid because USB is slow (although I don't see any reason why storage vm would have to write anything). – Henno May 02 '11 at 18:18
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    @Henno - yes, the usb stick would be slow. But more concerning than that is the fact that it will br horribly unreliable. As I mentioned already, USB sticks are designed for temporary storage of non-critical data. You have plenty of SAS drives - use them! – EEAA May 02 '11 at 20:17
  • @Henno, how are you planning to present these disks to the `vm anyway, via pci passthrough or as .vmdk/rdms? – Chopper3 May 02 '11 at 21:20
  • I was planning to follow the guide: pci passthrough. Since ESX 4.1 does not allow USB to be a datastore, I'll see if I can somehow hide a sata drive inside that 2U chassis. Actually that would be indeed a safer solution: when someone pulls a stick out, that stick can be a brick in an instant. – Henno May 02 '11 at 21:33
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    And finally we get there!!! – Chopper3 May 02 '11 at 21:45
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Further digging has not found the doc that I wanted. Not sure the latest version of VMware vSphere will access a USB device as a data store.

4.1 supports USB passthrough but perhaps I mis-read the USB store. Still looking for the doc.

Not sure a thumb drive would be a good one in any case.

Dave M
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  • Would you find me a reference for that please? I've looked and can't find one, no doubting you but it would be great to see it listed. – Chopper3 May 02 '11 at 15:01
  • Looking for doc now. Thought it was in a VMware news release – Dave M May 02 '11 at 18:36
  • http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1022290 This seems to indicate that you can passthrough USB storage to a VM, but it appears the primary purpose of this feature is to allow support for usb license keys such as HASP – ITGuy24 May 25 '11 at 19:24