Affordable storage for the SME, part one
by Johan De Gelas on November 7, 2007 4:00 AM EST- Posted in
- IT Computing
Conclusion so far
This was our second attempt (the first attempt can be seen here: Promise VTRAK j300s) at professional storage benchmarking. We want to remind our readers that the objective was not to compare the Intel SSR212MC2 and the Promise VTRAK E310f directly: the target market is quite different, with only a moderate amount of overlap. The main reason that we reviewed them together is that they are the representatives of affordable SAN storage arrays.
The Promise VTRAK E310f is a very attractive alternative to the expensive FC SANs of the big storage vendors. It targets medium sized enterprises, which will like the excellent storage capacity scalability via FC switches and JBODs. Promise keeps the total price of a small SAN lower thanks to the fact that you can choose which FC switch, HBAs, and hard drives you want to buy. The counterargument is of course that having only one vendor to blame for problems is easier, but incompatibility/interoperability problems are easy to avoid if you follow Promise's certification documents and guidelines. Promise's support might not be as luxurious as the big OEMs, which offer next business day on site support, but the support is free.
According to Promise you get 24/7 support (by phone only) which covers all Promise subsystems (M-Class, E-Class and J-Class). Email support is available five days a week (Monday - Friday). Support representatives can help on all subsystem related issues and/or questions and can also process RMAs (including advance replacements). Support is worldwide.
So where is the catch? Promise is relatively new to the SCSI/SAS/SAN world. That means that their products lack some of the more advanced features that the well-established players provide. One of the very handy ones is the ability to make snapshots - backups without any interruption of service. More advanced failover capabilities are limited to the Windows world. Promise has still some way to go before it can be an alternative to the big players for every storage buyer, but it will certainly attract some of the price conscious buyers.
The Intel SSR212MC2 naturally appeals to techies like us. At a very low price you can get a NAS, an iSCSI SAN, and a "normal" server all in one. The caveat is that you need to know what you are doing and need to be capable of installing a Linux iSCSI target for example. Without the proper knowledge, the price advantage will evaporate as you try to configure the system. It is also impossible to get the Microsoft target separately (it is only sold to OEMs), so you must have some Linux knowledge if you want to do it yourself. The alternative Windows iSCSI target (StarWind) we tried so far did not convince us, and the free MySAN iSCSI target is very limited.
That doesn't mean that this storage server is only suited for storage DIYers. At a slightly higher price, you can get this storage server completely ready to deploy with the iSCSI target configured and more. In that case, it is just a matter of checking how the reseller will support you, and you need a lot less (storage) knowledge to configure and troubleshoot. You can get this server with both Microsoft's iSCSI target as with user friendly (and quick to setup) Linux based iSCSI targets such as Open-E.
Promise VTRAK E310f Advantages
Intel SSR212MC2 advantages
So is iSCSI really an alternative to fiber channel? What about CPU load, network load, and TCP/IP offloading? We also need to explain some of the weird performance issues we've encountered. However, as this article is getting too long already, we decided to do more in depth testing for our next article.
This was our second attempt (the first attempt can be seen here: Promise VTRAK j300s) at professional storage benchmarking. We want to remind our readers that the objective was not to compare the Intel SSR212MC2 and the Promise VTRAK E310f directly: the target market is quite different, with only a moderate amount of overlap. The main reason that we reviewed them together is that they are the representatives of affordable SAN storage arrays.
The Promise VTRAK E310f is a very attractive alternative to the expensive FC SANs of the big storage vendors. It targets medium sized enterprises, which will like the excellent storage capacity scalability via FC switches and JBODs. Promise keeps the total price of a small SAN lower thanks to the fact that you can choose which FC switch, HBAs, and hard drives you want to buy. The counterargument is of course that having only one vendor to blame for problems is easier, but incompatibility/interoperability problems are easy to avoid if you follow Promise's certification documents and guidelines. Promise's support might not be as luxurious as the big OEMs, which offer next business day on site support, but the support is free.
According to Promise you get 24/7 support (by phone only) which covers all Promise subsystems (M-Class, E-Class and J-Class). Email support is available five days a week (Monday - Friday). Support representatives can help on all subsystem related issues and/or questions and can also process RMAs (including advance replacements). Support is worldwide.
So where is the catch? Promise is relatively new to the SCSI/SAS/SAN world. That means that their products lack some of the more advanced features that the well-established players provide. One of the very handy ones is the ability to make snapshots - backups without any interruption of service. More advanced failover capabilities are limited to the Windows world. Promise has still some way to go before it can be an alternative to the big players for every storage buyer, but it will certainly attract some of the price conscious buyers.
The Intel SSR212MC2 naturally appeals to techies like us. At a very low price you can get a NAS, an iSCSI SAN, and a "normal" server all in one. The caveat is that you need to know what you are doing and need to be capable of installing a Linux iSCSI target for example. Without the proper knowledge, the price advantage will evaporate as you try to configure the system. It is also impossible to get the Microsoft target separately (it is only sold to OEMs), so you must have some Linux knowledge if you want to do it yourself. The alternative Windows iSCSI target (StarWind) we tried so far did not convince us, and the free MySAN iSCSI target is very limited.
That doesn't mean that this storage server is only suited for storage DIYers. At a slightly higher price, you can get this storage server completely ready to deploy with the iSCSI target configured and more. In that case, it is just a matter of checking how the reseller will support you, and you need a lot less (storage) knowledge to configure and troubleshoot. You can get this server with both Microsoft's iSCSI target as with user friendly (and quick to setup) Linux based iSCSI targets such as Open-E.
Promise VTRAK E310f Advantages
- Offers excellent all around performance...
- ... even with RAID 6!
- Attractive price for the storage rack...
- ... low price when you start building the complete SAN
- You are the one who decides which drives and switches you want to use
- Excellent Capacity scalability (thanks to JBODs) with little hassle
- Easy to use and rich web based management interface
- Low cost but 24/7 Support
- No multipath HA drivers for Linux yet
- Not suited for SMEs without any storage knowledge - you will want (expensive) onsite support in that case
- e610f (3U) probably has a better performance/capacity/price ratio
Intel SSR212MC2 advantages
- Very flexible: Can combine a NAS and iSCSI
- Very flexible part 2: Can combine a server and a storage server into one server
- Very low price, especially if you build it yourself
- You can get a fully loaded OEM version from various resellers - slightly more expensive but less knowledge required
- Support will depend on the reseller, which can be good news
- Support could also be bad - support will depend on the reseller you chose
- Supports 32 drives at most (limited JBOD expansion)
- RAID 6? Slightly older IOP processor...
- Performance depends a lot on the chosen iSCSI target and configuration
So is iSCSI really an alternative to fiber channel? What about CPU load, network load, and TCP/IP offloading? We also need to explain some of the weird performance issues we've encountered. However, as this article is getting too long already, we decided to do more in depth testing for our next article.
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Anton Kolomyeytsev - Friday, November 16, 2007 - link
Guys I really appreciate you throwing away StarWind! W/o even letting people know what configuration did you use, did you enable caching, did you use flat image files, did you map whole disk rather then partition, what initiator did you use (StarPort or MS iSCSI), did you apply recommended TCP stack settings etc. Probably it's our problem as we've managed to release the stuff people cannot properly configure but why did not you contact us telling you have issues so we could help you to sort them out?With the WinTarget R.I.P. (and MS selling it's successor thru the OEMs only), StarWind thrown away and SANmelody and IPStor not even mentioned (and they are key players!) I think your review is pretty useless... Most of the people are looking for software solutions when you're talking about "affordable SAN". Do you plan to have second round?
Thanks once again and keep doing great job! :)
Anton Kolomyeytsev
CEO, Rocket Division Software
Johnniewalker - Sunday, November 11, 2007 - link
If you get a chance, it would be great to see what kind of performance you get out of an iscsi hba, like the one from qlogic.When it gets down to it, the DAS numbers are great for a baseline, but what if you have 4+ servers running those io tests? That's what shared storage is for anyhow. Then compare the aggregate io vs DAS numbers?
For example, can 4 servers can hit 25MB/s each in the SQLio random read 8kb test for a total of 100MB/s ? How much is cpu utilization reduced with one or more iscsi hba in each server vs the software drivers? Where/how does the number of spindles move these numbers? At what point does the number of disk overwhelm one iscsi hba, two iscsi hba's, one FC hba, two FC hbas, and one or two scsi controllers?
IMHO iscsi is the future. Most switches are cheap enough that you can easily build a seperate dedicated iscsi network. You'd be doing that if you went with fiber channel anyhow, but at a much higher expense (and additional learning curve) if you don't already have it, right?
Then all we need is someone who has some really nice gui to manage the system - a nice purdy web interface that runs on a virtual machine somewhere, that shows with one glance the health, performance, and utilization of your system(s).
System(s) have Zero faults.
Volume(s) are at 30.0 Terabytes out of 40.00 (75%)
CPU utilization is averaging 32% over the last 15 minutes.
Memory utilization is averaging 85% over the last 15 minutes.
IOs peaked at 10,000 (50%) and average 5000 (25%) over the last 15 minutes.
Pinch me!
-johhniewalker
afan - Friday, November 9, 2007 - link
You can get one of the recently-released 10Gbps PCI-E TCP/IP card for <$800, and they support iSCSI.here's one example:
http://www.intel.com/network/connectivity/products...">http://www.intel.com/network/connectivi...oducts/p...
The chip might be used by Myricom and others, (I'm not sure), and there's a linux and a bsd driver - a nice selling point.
10gb ethernet is what should really change things.
They look amazing on paper -- I'd love to see them tested:
http://www.intel.com/network/connectivity/products...">http://www.intel.com/network/connectivi...ucts/ser...
JohanAnandtech - Saturday, November 10, 2007 - link
The problem is that currently you only got two choices: expensive CX4 copper which is short range (<15 m) and not very flexible (it is a like infiniband cables) or Optic fiber cabling. Both HBAs and cables are rather expensive and require rather expensive switches (still less than FC, but still). So you the price gap with FC is a lot smaller. Of course you have a bit more bandwidth (but I fear you won't get much more than 5 GBit, has to be test of course), and you do not need to learn fc.Personally I would like to wait for 10 gbit over UTP-cat 6... But I am open to suggestion why the current 10 gbit would be very interesting too.
afan - Saturday, November 10, 2007 - link
Thanks for your answer, J.first, as far as I know, CX4 cables aren't as cheap as cat_x, but they aren't all _that_ expensive to be a showstopper. If you need more length, you can go for the fibre cables -- which go _really_ far:
http://www.google.com/products?q=cx4+cable&btn...">http://www.google.com/products?q=cx4+ca...amp;btnG...
I think the cx4 card (~$800)is pretty damn cheap for what you get: (and remember it doesn't have pci-x limitations).
Check out the intel marketing buzz on iSCSI and the junk they're doing to speed up TCP/IP, too. It's good reading, and I'd love to see the hype tested in the real world.
I agree with you that UTP-cat 6 would be much better, more standardized, much cheaper, better range, etc. I know that, but if this is we've got now, so be-it, and I think it's pretty killer, but I haven't tested it : ).
Dell, cisco, hp, and others have CX4 adapters for their managed switches - they aren't very expensive and go right to the backplane of the switch.
here are some dell switches that support CX-4, at least:
http://www.dell.com/content/products/compare.aspx/...">http://www.dell.com/content/products/co...er3?c=us...
these are the current 10gbe intel flavors:
copper: Intel® PRO/10GbE CX4 Server Adapter
fibre:
Intel® PRO/10GbE SR Server Adapter
Intel® PRO/10GbE LR Server Adapter
Intel® 10 Gigabit XF SR Server Adapters
a pita is the limited number of x8 PCI-E slots in most server mobos.
keep up your great reporting.
best, nw
somedude1234 - Wednesday, November 7, 2007 - link
First off, great article. I'm looking forward to the rest of this series.From everything I've read coming out of MS, the StorPort driver should provide better performance. Any reason why you chose to go with SCSIPort? Emulex offers drivers for both on their website.
JohanAnandtech - Thursday, November 8, 2007 - link
Thanks. It is something that Tijl and myself will look into, and report back in the next article.Czar - Wednesday, November 7, 2007 - link
Love that anandtech is going into this direction :DRealy looking forward to your iscsi article. Only used fiber connected sans, have a ibm ds6800 at work :) Never used iscsi but veeery interested into it, what I have heard so far is that its mostly just very good for development purposes, not for production enviroments. And that you should turn of I think chaps or whatever it its called on the switches, so the icsci san doesnt overflow the network with are you there when it transfers to the iscsi target.
JohanAnandtech - Thursday, November 8, 2007 - link
Just wait a few weeks :-). Anandtech IT will become much more than just one of the many tabs :-)
We will look into it, but I think it should be enough to place your iSCSI storage on a nonblocking switch on separate VLAN. Or am I missing something?
Czar - Monday, November 12, 2007 - link
think I found ithttp://searchstorage.techtarget.com/generic/0,2955...">http://searchstorage.techtarget.com/generic/0,2955...
"Common Ethernet switch ports tend to introduce latency into iSCSI traffic, and this reduces performance. Experts suggest deploying high-performance Ethernet switches that sport fast, low-latency ports. In addition, you may choose to tweak iSCSI performance further by overriding "auto-negotiation" and manually adjusting speed settings on the NIC and switch. This lets you enable traffic flow control on the NIC and switch, setting Ethernet jumbo frames on the NIC and switch to 9000 bytes or higher -- transferring far more data in each packet while requiring less overhead. Jumbo frames are reported to improve throughput as much as 50%. "
This is what I was talking about.
Realy looking forward to the next article :)