# new freebsd install / raid5 question



## vso1 (Jun 24, 2010)

I've bought a new system (adm 4850e cpu (1,6ghz dual core), 2gb ram highpoint rocketraid pci sata card) 

ps the rocketraid card is just used for additional sata connections no hardware raid 


some different sized drives including 4x 1tb WD green drives 
smallest disk 120gb 

due to the fact I want to use the Freebsd box primairily for 
- ISCSI connections (also together with Gpxe & iscsi boot for diskless booting for my home desktops) 
other things 
- ups controller (seperate topic/research) 
- gateway/router (between internet gateway and rest of network because 100mb would degredate my network performance. ) 
- centreon/nagios (just to do some basic monitoring)


is Gvinum for software raid the way to go ? ZFS like it says its a fs where I have no need for such a file system.  are there alternatives ? 
what would the best raid config, (how do i include more drives) if I read the gvinum manual correctly ? I could add drive space currently not used to 1 big raid5 config ? 

So (current possible disk layout) 
4x 939 GB (or something like that 
1x 320 (100gb allocated to FreeBSD) 
1x 120 gb (unused) 
1x 160 gb (unused) 
- (to be added later) 
- (to be added later)
- (to be added later)

If Iscsi booting works then the disks from the desktops would move --> to the NAS server 
over time those disks (when they fail) will get replaced by bigger disks

Currently I have speed issue regarding ISCSI/Disks however thats a seperate topic(on this forum) 

what tweaking do you guys/girls suggest to me? regarding: 
- kernel 
- sysctl ?
- software raid 
- additional packages(Maybe) 

thx in advance


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## Matty (Jun 24, 2010)

maybe you should take a better look at ZFS because frankly it is more then a FS.


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## vso1 (Jun 24, 2010)

Matty said:
			
		

> maybe you should take a better look at ZFS because frankly it is more then a FS.



Can you give me a bit more details? (differences for example?) Gvinum looks the better choice. 

*explaination*

When i do # zpool raidz <disks>  I also get a /raidzvolume .. what I don't need 
if the performance is better when I do x.y.z instead when using gvinum that would be intresting to know. 

I need 
- redundancy (if 1 disk fails ...) 
- ability to expand raid volume 

Any speed bonus against normal (singel)disk operation is an (major) advantage but redundacy is my primairy goal.


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## Matty (Jun 24, 2010)

vso1 said:
			
		

> Can you give me a bit more details? (differences for example?) Gvinum looks the better choice.
> 
> *explaination*
> 
> When i do # zpool raidz <disks>  I also get a /raidzvolume ..



well raidz1 = raid5

true on the expansion problem but you could create a raid10 setup which allows you to add a new 2 disk mirror for storage expansion and which give you good performance which could be handy if you like to use it to boot an image for your desktop.


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## vso1 (Jun 24, 2010)

jup raidz is/was intressting 

RAID 10 = overkill 
stripe/mirror is obvious 

I choise raid5 because losing 1 disk is an calculated risk, 
in terms of "relative speed" (not fact but fictional numbers below) 
single disk = 100% speed
single vs mirror = 75%  speed
single vs stripe = 200%  speed
single vs *raid5(4 disks) = 125% to 150%* speed
single vs raid10 = 175% to 200%  speed

then I see raid5 as the "best" home based solution, in terms of 
- cost
- power consumption 
- speed/redundancy

please note that it's for home use, so evenings and weekends max a few users 



I can drive to the computer dealer "alternate" since i have the room to add another 4 Don't have the money yet .. so need to do what i have now


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## Matty (Jun 24, 2010)

random io sucks on singe raidz but thats another discussion.
zfs raid10 has the advantage of being able to add another 2disk mirror as another vdev meaning you are able to add 1 or 2TB very easily where with 4 disk raidz you would need another 4 disks to expand your pool.


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## vso1 (Jun 25, 2010)

Matty I am going (reluctantly) to zfs because the gvinum raid + 4kib sector disks are nightmare(ish) 
I don't want to spend money on to much performance gain, 

Previous experiance with ZFS was a nightmare (p4 system with pci bus disks) in combination with disk allignment issue ? (now I've made a slice on the disk gave it the "correct" allignment I hope 

I have to reinstall tough because I am going to add more RAM in te future if this works out, going from I386 to amd64 

beware that its for home use, made with off-the-shelf hardware not 19" rack servers. 
I don't think the wife(and child) is going to agree with a lot of noice & dry bread for daddy's hobby  

seriously, I am just searching for the best redundancy vs price vs performance option(s) any help is appriciated


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