I'm glad that I could help.
Yes, while USB3 has an impressive interface (and thus potential) speed of
up to 5 gbps (or over 600 MB/sec) the actual hardware normally provides
speeds which for basic DOKs are even under USB 2.0 spec. in most cases
(under 60 MB/sec.).
However, as I also mentioned, it will only affect the time it takes to
load, and from my experience with any decent DOK it's quite OK, you don't
even have to invest into ultra-expensive and ultra-fast one, especially if
you don't plan to "re-burn" the DOK very often.
Thanks in advance,
On Mon, Jun 26, 2017 at 8:05 PM, Michael McConachie <
That's exactly what I thought; you hit all the points (including slow DOM
SATA I type performance vs. USB3 speeds). That's all I needed
clarification on, before running down the rabbit hole.
*From:* Lev Veyde <lveyde(a)redhat.com>
*Sent:* Monday, June 26, 2017 4:00 PM
*To:* Michael McConachie
*Subject:* Re: [ovirt-users] oVirt Live USB3 question
oVirt-Live's basically functions as any other LiveCD, so no special
Generally it means that necessary kernel/kernel modules/programs are
loaded into RAM, and access to the image is needed if e.g. one wants to run
some more programs.
All writes are done into RAM.
Note however that since the whole CD isn't copied into RAM, so you still
need it to be accessible, e.g. have the USB DOK be inserted into the
As you already mentioned the oVirt-Live is designed to work in a sandboxed
environment as far as the network is concerned.
It was never designed nor tested to work with i.e. external storages, as
in order to do so the network configuration will have to be modified.
Regarding performance: we haven't tested it, but probably the oVirt-Live
may take a bit more time to load when compared to normal installation.
This is because USB DOKs are generally slower than SAS/SATA HDDs/SSDs.
Once loaded however the performance will be similar and in some cases even
greater, since all writes are done to the RAM.
The price of this is of course that once the system is rebooted for
whatever reason all data is lost.
Hope it helped,
On Sat, Jun 24, 2017 at 5:10 AM, Michael McConachie <
> Hi all,
> Potentially stupid question here. Sorry in advance if so. I have always
> built out full blown multi rack instances of oVirt, and RHEV for clients,
> but the following question has me wondering before I go digging and trying
> it out...
> I realize that the oVirtLive ISO is for demo purposes, sandboxing, and
> not production: I have a client, who is in need of a bootable AIO-based USB
> install with the caveat of being able to connect to the computer's HD and
> other external storage at that point (for the Storage and ISO domains that
> I'll create afterwards). This is because they have one BM to work with and
> they don't want the extra overhead using an SSD HD slot. They don't want to
> use a Sata DOM either if possible.
> In saying that, and concerning the oVirt LiveISO capabilities - I have
> two questions.
> - Does the AIO USB install load necessary runtimes into memory, similar
> to esxi bootable USBs and utilize the base hardware afterwards so that the
> rest of the operations are ran in memory, hitting the disk (USB in this
> case) like a normal OS load when needed for kernel calls, etc..??
> - Are there a terrible performance costs if we stay with USB3 (which has
> a ridiculous theoretical speed in certain hardware matching situations)?
> Thanks in advance for anyone who might have already crossed this bridge
> and can provide insight.
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