One for IT guys

[Delboy]

clearly i need to come bavl and read this when im sobber, i know my nax is raid 5. so the big wuestion is what should i be doinf ?

Originally Posted by moltuae

Well, firstly I wouldn't bother with RAID 5 even if it was an option. RAID 5 pretty much became useless several years ago once drive capacities began exceeding 2TB:
http://www.zdnet.com/article/why-rai...rking-in-2009/

For my business customers, where possible I always choose RAID 10 or RAID 1, especially for mission-critical servers. The reason for using mirrored RAID arrays of course is to provide fault tolerance. In other words, it's a convenience thing, rather than a 'backup', to reduce down-time in the event of a drive failure.

So, it depends on how mission-critical your system is. If reducing down-time was an important factor, I'd use a pair of drives in RAID 1 and perhaps keep the remaining bay as a hot swap, backup drive or just extra storage for less important files. If, on the other hand, down-time was less important than storage capacity, I'd probably use 3 drives in RAID 0. As long as everything is backed up, a failed drive just means the server is going to be down for a while until you've replaced it and recovered from backups.

Also, how are you calculating the power consumption comparisons? I would be surprised if the difference is that great.


How much would you be looking to sell the Poweredge for? And does it come with dual PSUs and rack rails?

[HPsauce]

Surely the type of RAID you chose depends on what you want to achieve, e.g. performance, redundancy, fast-fix, rapid recovery etc.
Some while since I bothered with this, but the servers I last was "responsible" for were all at least RAID 5 with hot-swap drives, mainly Dell kit.
So if anything failed you just yanked it out and plugged a replacement in while still running. The array was then rebuilt automatically at a hardware/firmware level.

IIRC there was another variant (can't recall which) that was secure against a 2-drive failure. We used that on really critical stuff. My excuse is that I was an IT manager/director not a techie!

[Adrian E]

I can see the point Mark is making - if the typical read error rate of a large capacity drive is inevitably higher than the error rate that a RAID array can cope with rebuilding from, you're doomed to fail....

Mine's basically a media server for TV/music/films that happens to maintain backups of my desktop and laptop, so there's nothing critical on there. I guess RAID 5 with a load more discs reduces the chances of a failed drive causing a failed rebuild as the missing data may be on another drive?

Just replaced the desktop HDD with a 4TB WD Black due to running short of space! Elsawin takes up a shed load....

At some point I really should sort out a cloud based/off site backup option, given a house fire would lose us everything digital!

[moltuae]

Originally Posted by Delboy

clearly i need to come bavl and read this when im sobber, i know my nax is raid 5. so the big wuestion is what should i be doinf ?

Sai Wut?


Well, as long as you have backups, I wouldn't worry about it too much. Essentially, the problem with RAID 5 is that, by the nature of how it works, the amount of data that has to be written to rebuild an array of large capacity drives (>2TB) after a replacing a failed drive, exceeds that of the theoretical failure rate of most mechanical drives. Therefore, the chances of further data write failures during rebuild becomes likely.

In enterprise environments, most systems administrators have known about the dangers of RAID 5 for years so it's relatively uncommon. For residential use, RAID 5 is still surprisingly popular, but then having a server/NAS fail in a home-setup will probably be nothing more than inconvenient.

You do have to remember that RAID data mirroring is a convenience thing. Some people confuse the data mirroring aspect of it with backing up, which of course it's not. Everything is mirrored between drives, including corruptions and all deletions (be it intentional or malicious).

RAID 1/10 is generally considered 'best practice' amongst most IT professionals who work with medium to large businesses. For my server setups, I generally have a pair of SSDs in RAID 1 for the Operating System and RAID 10 for both the internal storage and NAS/SAN external storage and backup devices. Rarely do the severs or storage devices I install have any less than 4 bays though.

If you have less than 4 bays available, and you need the convenience of being able to swap-out a failed drive with little-to-no down-time, I'd recommend RAID 1. If you don't need that convenience, RAID 5 is fine, though bear in mind that it (theoretically at least) provides little more fault tolerance than RAID 0.

Originally Posted by HPsauce

Surely the type of RAID you chose depends on what you want to achieve, e.g. performance, redundancy, fast-fix, rapid recovery etc.

Precisely.

[Adrian E]

With 4 identical drives in RAID5 am I likely to get away with a single drive failure and rebuild (ie is it likely any missing segments of date from a failed read will be available from elsewhere in the RAID?)

I was running mirrored with 2 drives but ran out of space, so expanded it with 2 more drives and went to RAID5 at that point....

[moltuae]

Originally Posted by Adrian E

With 4 identical drives in RAID5 am I likely to get away with a single drive failure and rebuild (ie is it likely any missing segments of date from a failed read will be available from elsewhere in the RAID?)

I was running mirrored with 2 drives but ran out of space, so expanded it with 2 more drives and went to RAID5 at that point....

It's hard to say, since it depends on the capacity of the hard drives and how much reading/writing has to be done to rebuild the data. Since RAID 5 uses parity to recreate the data (rather than simple duplication), rebuilding can be very disc intensive. Also, if one drive of four identical drives has failed, there's a good chance the remaining drives could be about to fail too and working them hard to rebuild the data might just push them over the edge.

Having said all that, there's a chance the drives might last better than expected and rebuilding may well succeed, but if you want to vastly improve your chances, with 4 drive bays, you could create a RAID 10 array instead.

[ainarssems]

Might depend what software you're running on the hp microserver

I am currently running Windows 7 as OS on Dell and will probably run it on HP as well, mostly for ease of setup. From software I run local file sharing, internet file sharing, FTP, VPN, Plex, CCTV... Will probably need to upgrade CPU and RAM to 8GB to run CCTV on HP

I've just setup a Microserver Gen8 at home, from what I can work out from my smart meter its consuming about 85watts of power running 4 HDDs, a single SSD in the ODD bay and upgraded to 16GB Ram.

That's interesting, from my research on the net before buying others have reported about 33W power consumption in idle. I measured mine to be 30W in idle with 1 HDD, maybe it's the Red HDD's consuming more power?

Well, firstly I wouldn't bother with RAID 5 even if it was an option. RAID 5 pretty much became useless several years ago once drive capacities began exceeding 2TB:
http://www.zdnet.com/article/why-rai...rking-in-2009/

That's something to consider and I was not aware off.

So, it depends on how mission-critical your system is.

It's not critical, more of pain in the ass if not working. Dell have served me well couple of years, only one HDD failed once, just bough a new one and swapped without powering down so no downtime.

Also, how are you calculating the power consumption comparisons?

Measured with one of these: http://www.ebay.co.uk/itm/2909576441...%3AMEBIDX%3AIT Seems accurate enough as it reads 18W lightbulb as 17.2W and 2200 W kettle as 2250W. Interesting fact on TV as well, without Eco mode it takes 110W, in maximum power saving mode only 58W, was not expecting that big of a difference.

How much would you be looking to sell the Poweredge for? And does it come with dual PSUs and rack rails?

I was hoping to get at least 100 notes for ti, hard to judge the price, they are all over the price on e-bay depending on configuration. I think it did not have rails, need to check but does have 2x750W PSU's

Just replaced the desktop HDD with a 4TB WD Black due to running short of space! Elsawin takes up a shed load....

I only have 250GB SSD on Desktop, ElsaWin is running on server as well and just a small 30MB client installed on desktop and laptops to run it from server. I can even run it remotely if I VPN in the home network.

I think I might try ESXi on USB and use all for HDD's in 1+0 then

[moltuae]

Originally Posted by ainarssems

I was hoping to get at least 100 notes for ti, hard to judge the price, they are all over the price on e-bay depending on configuration. I think it did not have rails, need to check but does have 2x750W PSU's

I might give you 100 quid for it, depending on the condition and further details. If you're not in a hurry to sell it, bring it to the next meet and I'll probably buy it off you.

[tonupkid]

Years ago I had a home server, with 5 x 200Gb disks, and indeed 3 of them failed over a very short period. Now I have a NAS.
When my work HP server starts wobbling, it will be replaced with a NAS. I can't see the benefit of a server, and its complexity and expense, over the simplicity of a NAS.

[moltuae]

Originally Posted by tonupkid

I can't see the benefit of a server, and its complexity and expense, over the simplicity of a NAS.

For use as a simple home 'file server', I'd totally agree.

Of course a proper server can do so much more than any NAS though and in most larger businesses you'll usually find several of each, all serving different purposes. One of my customers is presently running 16 servers (6 physical and 10 virtual) and 4 large capacity NAS units (for shared storage and backups).