Gmirror/graid or hardware raid?

Paul Pathiakis pathiaki2 at
Wed Jul 8 20:56:46 UTC 2015


You may want to even consider using ZFS and jails....

If you're going to run FreeBSD as the VMs, it's probably more efficient 
to run with jails and ZFS IMHO.

Also, you'll be able to create a lot more jails than you have cores as 
the resources are shared with jails.

Turn the PERC card into an HBA/RAID 0 so that all the targets can be 
seen individually as targets.  Then, use ZFS to create two RAID 1 zpools 
and then stripe them to create a RAID 10 array.  This will be 
extraordinarily fast in disk access.

All the RAID calculation will no longer be handled by the CPU on the 
card but by main CPU cores which are, typically, much faster than what's 
on a RAID card.  Also, with 16 GB of RAM and using jails, your could 
easily create large amounts of jails, dedicate a large amount of RAM 
(like 4-8 GB) to the ZFS cache and, basically, almost everything is 
going to be worked in memory courtesy of FreeBSD and ZFS.

I actually had a setup like this with over 50 jails running numerous Web 
servers.  After tuning the kernel to do web serving, making sure ZFS had 
enough memory, the load was very, very, trivial.

Think of jails as a stripped down version of Solaris zones.  Very little 
overhead, very secure and no resource demands outside of what it's using 
whereas with VMs from a vendor like VMWare or VirtualBox, you have to 
dedicate at least one core and some amount of disk space and, possibly, 
other resources.

WIth jails, all the jails share one kernel image (separate from the main 
OS) that is mounted as a nullfs to all of them.  They start and consume 
what they need.  The only downside is if you have a runaway process 
doing something.  I have yet to have one after creating hundreds of jails.

So, check into ezjail and/or other jail tools.  Read the Handbook on the 
web site and look up jails.  It may not be what you want, but from what 
you presented, you could use them.

(Before everyone jumps on me, this is a VERY SIMPLISTIC explanation I 
know, however, I'd like to think it's accurate for simplicity sake. :-) )

Just trying to help,


On 07/08/2015 15:49, Mario Lobo wrote:
> Hi;
> I'm building a server that is going to host VMs for a small e-commerce
> site. It's mainly going to be used for testing new solutions/improving the
> current site (on the cloud at this moment) but in the medium to long run,
> the idea is to hold the production site in it.
> Since I don't have any experience in running VMs for e-commerce, I don't
> know for sure if my plan is correct or even feasible.
> I want to use FBSD 10 as the host OS and the VMs will run under Virtual Box.
> It should be a Dell 430 server (or IBM equivalent) CPU Xeon E5-2630 with 4
> 2T SATA HDs/16 G Ram/ RAID PERC H730 controller (supported by mrsas).
> All VMs will run FBSD also with usual Apache/php/Mysql combination.
> I really would welcome suggestions/opinions on what would be the most
> efficient way to set up those HDs to hold these virtual disks.
> I thought about zfs but I won't have lots of RAM avaliable. Should I use
> the controller raid? Gmirror/Graid? What raid level?
> Thanks in advance for any thoughts on this.

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