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SoHo NAS With Good Network Throughput?
An anonymous reader writes "I work at a small business where we need to move around large datasets regularly (move onto test machine, test, move onto NAS for storage, move back to test machine, lather-rinse-repeat). The network is mostly OS X and Linux with one Windows machine (for compatibility testing). The size of our datasets is typically in the multiple GB, so network speed is as important as storage size. I'm looking for a preferably off-the shelf solution that can handle a significant portion of a GigE; maxing out at 6MB is useless. I've been looking at SoHo NAS's that support RAID such as Drobo, NetGear (formerly Infrant), and BuffaloTech (who unfortunately doesn't even list whether they support OS X). They all claim they come with a GigE interface, but what sort of network throughput can they really sustain? Most of the numbers I can find on the websites only talk about drive throughput, not network, so I'm hoping some of you with real-world experience can shed some light here."
FreeNAS or OpenFiler on a PC with a raid controller and GigE should work. It might even be cheaper than a NAS box.
As to OS/X support. I thought OS/X supported Windows networks out of the box. Odds are very good that if it supports Windows OS/X will work.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
You might as well build it yourself.
Go get a lowbie Core2, mobo, good amount of ram, and 4 1TB disks. Install Ubuntu on them with LVM and encryption. Run the hardening packages, install Samba, install NFS, and install Webmin.
You now have a 100% controlled NAS that you built. You can also duplicate it and use DRBD, which I can guarantee that NO SOHO hardware comes near. You also can put WINE on there and Ming on your windows machines for remote-Windows programs... The ideas are endless.
If you want decent throughput build it yourself. Seriously. I have a coworker that bought 5 different NAS devices to do a bakeoff for a small skunkworks office and they all sucked for throughput. We ended up buying a $1K NAS that still wasn't great but sure beat all the SOHO ones. Numbers were ~8MB/s max on the fastest SOHO unit vs 25MB/s on the midrange one.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
One more thing: if it says gigabit ethernet, for me that usually means anywhere between 200-800Mbps of speed on a fairly busy network, which should suffice for large data backups in a matter of say 2-5 minutes tops for moving several gigs. Your throughput really depends on other factors, so yours may be higher or lower than mine but typically that range should suffice with the proper switching and routing equipment.
In terms of cost/benefit ratio, nothing beats a stripped down PC with a lot of drives stuffed in it or in an external esata enclosure. I run a HP NAS MV2020, and a linksys NAS200 and they both cant hold a candle to a PC in throughput. Ive heard of some commercial systems out there, but they cost a small fortune. Just my $.02
Good-bye
If you use a single disk NAS solution and you are doing sequential reads through your files and file system, your throughput can't be greater than the read/write speed of a single disk, which is no where near GigE (1000 Gbps is about 125 MB/second ignoring network protocol overhead). So you will need RAID (multiple disks) in your NAS, and you will want to use striped RAID (RAID 0) for performance. This means that you will not have any redundancy, unless you go with the very expensive striped mirror or mirrored stripes (1+0/0+1). RAID 5 gives you redundancy, and isn't bad for read, but will not be that great for writes.
As you compare/contrast NAS device performance, be sure that you understand the disk architecture in each case and see oranges to oranges comparisons (i.e, how does each one compare with the RAID architecture that you are interested in using - NAS devices that support RAID typically offer several RAID architectures). Also be sure that the numbers that you see are based on the kind of disk activity you will be using. It doesn't do much good to get a solution that is great at random small file reads (due to heavy use of cache and read-ahead) but ends up running out of steam when faced with steady sequential reads through the entire file system where cache is drained and read-ahead can't stay ahead.
Once you get past the NAS device's disk architecture, you should consider the file sharing protocol. Supposedly (I have no authoritative testing results) CIFS/SMB (Windows file sharing) has a 10% to 15% performance penalty compared to NFS (Unix file sharing). I have no idea how Apple's native file sharing protocol (AFP) compares, but (I think) OS X can do all three, so you have some freedom to select the best one for the devices that you are using. Of course, since there are multiple implementations of each file sharing protocol and the underlying TCP stacks, there are no hard and fast conclusions that you can draw about which specific implementation is better without testing. One vendor's NFS may suck, and hence another vendors good CIFS/SMB may beat its pants off, even if the NFS protocol is theoretically faster than the CIFS/SMB protocol.
Whichever file sharing protocol you choose, its very possible it will default to operation over TCP rather than UDP. If so, you should pay attention to how you tune your file sharing protocol READ/WRITE transaction sizes (if you can), and how you tune your TCP stack (windows sizes) to get the best performance possible. If you use an implementation over UDP, you still have to pay attention to how you set your READ/WRITE buffer sizes and how your system deals with IP fragmentation if the UDP PDU size exceeds what fits in a single IP packet due to the READ/WRITE sizes you set.
Finally, make sure that your network infrastructure is capable of supporting the data transfer rates you envision. Not all gigabit switches have full wire-speed non-blocking performance on all ports simultaneously, and the ones that do are very expensive. You don't necessarily need full non-blocking backplanes based on your scenario, but make sure that whatever switch you do use has enough backplane capacity to handle your file transfers and any other simultaneous activity you will have going through the same switch.
Disk will always be. Since disk is your slowest spot you will always be disk I/O bound. So in effect there's no real reason to worry about network throughput from the NIC. NICs are efficient enough these days to just about never get bogged down. What you would want to look at for the network side would be your physical topology -- make sure you have a nice switch with nice backplane throughput.
About disks:
Your average fibre channel drive will top out at 300 IO/s because few people sell drives that can write any faster to the spindle (cost prohibitive for several reasons). Cache helps this out greatly. SATA is slightly slower at between 240-270 IO/s depending on manufacturer and type.
Your throughput will depend totally upon what type of IO is hitting your NAS and how you have it all configured (RAID type, cache size, etc). If you have a lot of random IO, your total throughput will be low once you've saturated your cache. Reads will always be worse than writes even though prefetching helps.
If you're working with multi-gigabyte datasets, you'll want to increase the number of spindles (ie number of disks) to as high as you can go within your budget and make sure you have gobs of cache. If you decide to RAID it, which type you use will depend on how much integrity you need (we use a lot of RAID 10 with lots of spindles for many of our databases). That will speed you up significantly more than worrying about the NICs throughput. don't worry about that until you start topping a significant portion of your bandwidth -- for example, say 60MB/sec sustained over the wire.
This doesn't get fun until you start having to architect petabytes worth of disk. ;)
A custom-built box, as many commenters suggested, seemed a tad inappropriate to me as he asked for an NAS device, not a server. Installing Ubuntu or whatever on it seems like more of a performance hit than a properly optimized "off the shelf" NAS box, since they most likely don't run Dbus, GNOME, Hald, bluetooth or any other desktop software atop the basic kernel and networking services.
While this is true, for noticably less than you'll pay for a NAS appliance, you can build a PC with vastly more CPU power and RAM (in particular, storage vendors - even with high-end, full-blown SAN solutions - are offensively stingy with cache), which will more than make up for any extra stuff that might be running.
You need to spend a LOT on an "appliance" type storage system to get something that has higher performance and/or better features than a "server". Particularly with cache, storage vendors across the board are offensively stingy (16 gigs of high-quality ECC RAM costs maybe $800, but you'll be lucky if your $100k SAN comes with half that amount).
Personally I would recommend the OP looks at Server/NAS-style "appliances" like Dell's NF500. They're the only sort of "cheap" turnkey devices he'll find that will deliver the performance he seems to want, and will probably only cost a grand or two more than DIY.
See, the problem with responses like this is that they ignore the request of the original poster, and, while being valid instructions for a home-built, it is only a good solution if the time of the OP has zero value. Your instructions involve eight steps: Order (multiple) parts, wait for delivery, assemble, learn how and then install OS, learn now and install three other packages. The OP is looking for three steps: Order one thing, wait for delivery, plug in and use.
Your post has value to the DIY crowd, certainly. But for someone looking for a product recommendation, it totally missed the boat.
For example:
Best home network NAS?
http://ask.slashdot.org/article.pl?sid=07/11/21/141244&from=rss
What NAS to buy?
http://ask.slashdot.org/article.pl?sid=08/06/30/1411229
Building a Fully Encrypted NAS On OpenBSD
http://hardware.slashdot.org/article.pl?sid=07/07/16/002203
Does ZFS Obsolete Expensive NAS/SANs?
http://ask.slashdot.org/article.pl?sid=07/05/30/0135218
What the hell? Is this the new quarterly NAS discussion?
Just disrupt the deflector shield with a tachyon burst.
A NAS is pretty much a server that is dedicated to storage.
If he wants to roll his own I would suggest either a light install of Ubuntu server or FreeNAS: http://www.freenas.org/. FreeNAS is based on the stripped down Free BSD core that m0n0wall uses. It is very small and is managed using a simple and easy to use web interface. I don't know about gigabit performance as I only set it up once for a friend using 100mbit. He had the Linksys NAS box and it was dog slow. On 100Mb it couldn't push more then 3-4 MB sec. I could get 8-9Mb sec using FreeNAS on an Athlon 1.3Ghz with 128MB ram and two SATA 500GB drives in RAID 1 (mirroring). He also added a USB 2.0 card to hook up another 500GB drive. It pretty much saturates his 100Mbit connection.
And here is my related question to others here:
I have fought with SAMBA on Ubuntu 8.04 server and I cant get it going faster than 10-11MB/sec when copying to/from Windows XP. Even with the tcp_nodelay setting and a few others it just barely breaks 11MB/sec. I can get 25-30MB sec when copying from one Windows PC to another. And the server hardware isn't puny: dual P4 2.4GHz Xeons, 4GB RAM, dual PCIX Intel gigabit and a PCIX SATA controller. Any one have any suggestions? NFS also runs at the same speed and when downloading from the Apache server I get 5-6MB sec. Something is wrong somewhere but I cant tell. I have changed kernels played with conf files but nothing works. Someone once told me SAMBA will always be slow but I don't believe that to be true.
The user believed he had increased performance, because his switch said "GigE" on it
Does his Cat 6 say "Monster Cable"?
I see even classic Slashdot is now pretty much unusable on dial up anymore.