[XCSSA] Recommendations for a SAMBA/NAS device?

[X-otic Computer Systems of San Antonio]

On May 22, 2009, at 6:32 PM, X-otic Computer Systems of San Antonio  
wrote:

> So never run software RAID-5 on the / system.. (processor affinity  
> or none).
> But yes.. SW-RAID-5 on / is bad juju. If you try to boot a RAID-5  
> system that
> is degraded.. I've literally seen it take 45 minutes to to boot the  
> system.
> During which time you're at high risk of losing everything if there  
> are ANY
> system hiccups.  And if it does hiccup or go down.. the filesystem  
> can easily
> be corrupted and data loss.
>
> Now.. that being said.. Offering out software RAID-5 from on another  
> system
> (such as a NAS box, SAN, file server or hybrid NAS/block level  
> system might
> be ok..) as long as IT boots off it's own system (preferably SDD,  
> flash, live
> CD, etc).  After all.. even hardware RAID is "software" at some  
> level. :)
> (same argument can be made for hardware firewalls vs software  
> firewalls to
> some degree).   And most of today's home NAS systems are just boxes  
> running
> embedded Linux+LVM+SW-RAID anyway. But I digress...
>
> But running SW-RAID on the same system that's running your OS on?..  
> meh..
> RAID-1 as most.. but I really wouldn't do much else.

Agreed. Our "Recommended MySQL DBA Server Config" is a RAID1 for OS  
and RAID10 for Data (with an optional RAID5 for backups if you really  
need the space and can afford a DAS). I think avoiding a RAID5 on / is  
good practice no matter if it is hardware of software RAID.
>
> One thing that I always recommend against is the cheap consumer
> motherboard/BIOS level and "thin" (proc/CPU-less) "hardware RAID".   
> Worst
> crap I've ever seen.. The BIOS/mobo variety is usually not supported  
> well (or
> at all) by Linux/UN*X unless it's an embedded higher end server  
> grade card or
> something (e.g. LSI, Adaptec, etc) with dedicated proc, battery  
> backed RAM
> and write back cache.  Usually buggy.. Rarely upgraded at the BIOS  
> flash or
> OS driver levels.  It's just a sales/marketing gimmick usually.  I  
> played
> with cheap mobo and "thin HW-RAID" cards in the 90's and have seen  
> people
> lose data too many times with low end promise cards ,etc.  Now I  
> would only
> use the previously mentioned LSI, Adaptec, 3ware, etc. You get what  
> you pay
> for.

Well, I would watch out for poor quality chipsets. I know nVidia has  
gotten some flak by their lack of (GPL) drivers. I think VIA is a  
reasonable bet, though. That said, if software RAID is being used (as  
opposed to the on chip "hardware" RAID options), you should be able to  
get by. I would, however, avoid Silicon Image SATA chipsets. They are  
terribly supported in FreeBSD and, while they do work in Linux, they  
tend to be buggy with poor vendor support.

Hardware raid is generally always a better option (although the Linux  
Software RAID tools I find superior to a RAID BIOS for configuration),  
but I agree - it needs to be real Hardware RAID. LSI, 3ware, and maybe  
Adaptec. I'm a bit critical of LSI for issues we've encountered at  
Rackspace. LSI forces battery conditioning (which also forced write- 
through mode) but lacks a good way to configure that. We have to get  
around it by preempting it. This could be avoided by, oh, I dunno,  
redundant batteries!

That said, even with that pitfall, hardware RAID is still a good way  
to go. I will say that I saw some interesting benchmarks with Sun  
hardware using both. Turns out, at least for that test, it was the  
best performing. I think it was pairs of hardware RAID1's with RAID0's  
in software (making a RAID10).
>

>> If it's the OS, my ultimate goal is a SW RAID1 of CF cards :)
>
> Not a bad idea if this is the OS that's only running the OS that is  
> in turn
> offering the HW-RAID NAS resources out to the network.  If that's  
> what you
> were talking about doing.. yeah. that sounds cool to me.. :)
>
> A somewhat "nicer" config might be to actually to run a Live-CD  
> based NAS
> distro with config stored on CF or thumb drive.  Rock solid setup.   
> This is
> how I do my network firewall.  Combine that setup with an  
> underclocked CPU
> with no fan and you've got an almost no-moving part system that's  
> thermally
> rock solid too (almost like an expensive embedded system).

It will indeed just be for NAS. Maybe I might use it for a bit of web- 
dev but I can run that off the storage array instead of off the CF. I  
did indeed think of a Live CD, or even seeing about booting from a USB  
stick instead of a full-blown CF card. That can be tricky, but is much  
easier to, say, clone it. Still need to figure that one out though.

>> That said, I could just backup to the Jungle :)
>
> Yeah.. one of us should do an XCSSA presentation on just this  
> subject! :)

Yeah I wouldn't use it to store TB's worth of data (you can, but it'll  
cost), but it's pretty cheap up to around 40GB. You could use that to  
backup the OS and the most important files pretty comfortably. It's a  
bit off topic, and I don't think it (yet) works, but I think the plan  
is also to allow being able to serve that data via a CDN. So, if you  
want, you can upload, say, images or movies using the Jungle and pull  
them down via an API. Pretty neat!

>
>
>
>> Anyways I went off on a tangent so I'll just stop here :)
>
> Don't we all? :)
>
>
> Sounds like one of us needs to do a home-brew NAS presentation.. tag  
> team
> maybe Tim? How about you Firestorm(Matt)?  Sounds like we have varied
> perspectives.  Might be cool. :)
>

Yep I think that would be cool too! I won't have my NAS ready for a  
bit but if someone wants to see some RAID and LVM magic, I'd be happy  
to share what I've learned.

Tim S.