On Fri, Aug 28, 2009 at 10:07 PM, Les Mikeselllesmikesell@gmail.com wrote:
Rudi Ahlers wrote:
The thing is, how will these kind of option perform in a hosting environment where downtime isn't at all an option. We have backup generators, UPS, load balanced networks, etc Even the Tyan / SuperMicro machines that I'm looking at will have redundant power supplies & hard drives.
But the one piece of of the puzzle that I don't understand, will a self-build-Linux NAS device, or even Openfiler / FreeNAS give us that kind of uptime.
High quality servers running an enterprise linux version can give you the same uptime as dedicated hardware if you are comfortable with not doing updates. For example I still have a RH 7.3 based box running that has only been down a few minutes in about 7 years (had to move it) but I wouldn't try that with anything exposed to the internet. I did replace several drives and rebuild the raids over that time - and it is probably about to die of old age soon.
But surely CentOS, or other free / non-enterprise linux's can do the same? I've seen NAS devices running Debian, so CentOS should be able to deliver the same performance / reliability ?
The other thing which I would like to also get to, is that we could do more with a Linux based distro than with a off-the-shelf NAS. For example I could setup storage space for users and build custom applications that could manage it all - for example give a hosting client a reseller account with 1TB space and he could resell that to his clients. And I could go as far as setting up SMB / NFS / iSCSI / rsyn / SSH / FTP / sFTP / podcast / HTTP / etc, i.e. other protocols which a NAS may not necessarily support. And I could even use it as a dedicated web farm if I feel like it, running HTTP & MySQL as well if the server has enough RAM & CPU.
Ideally I would like have a highly-redundant storage device which can be used by numerous users, and also host Virtual Machines on it. So IO will be the biggest concern, in terms of speed, with reliability the 2nd biggest concern.
I'll run RAID 10 (1+0) for speed & reliability, and use 1TB / 1.5TB RAID edition server grade SATAII hard drives with hardware RAID - although I also think software RAID on a decent CPU could perform better. But the hardware RAID cards have battery backup which gives better reliability. Then I would like to build 2 devices, each syncing with the other one.
The 2 device failover is the tricky part and it introduces some new ways to fail. I've always preferred to keep things simple with mirrored disks in a hot-swap chassis so the likely failure (single disk) doesn't slow down operation and can be replaced at a convenient time. The less likely motherboard or power supply failure will cause some down time while you swap the disks into a spare chassis, though. And you still need off-site backups to cover other types of problems.
The other question is, how well will my own Linux / UNIX based NAS perform? Surely these companies who build their own NAS devices spend a lot of time fine-tuning the OS to deliver the best performance, and probably spend a lot of time researching and testing different hardware devices and configurations to see what works best?
I'd try the canned openfiler/nexentastore installs to see if they meet your needs in terms of functionality and performance and if so, then decide whether you want to use a supported version or duplicate their work setting up something on generic linux/opensolaris.
-- Les Mikesell lesmikesell@gmail.com
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