Now if I throw iSCSI into the mix, connecting the LUN on a Server R2 system, I still get similar read speeds, but writes fluctuate constantly from a few kbps to a peak of 35mbps, sometimes even appearing like its doing nothing network throughput stats in task manager, this is irrespective of the data transfer being small or large files.
ISCSI vs. FC performance: A closer look at storage
I've spent ages trying to explore some of the options in iSCSI Initiator but can't find anything that seems to be affecting the performance, I'm not using encryption as I'm aware that would reduce performance further.
Enabling Windows write caching on the mounted LUN does give me the "illusion" of a speed boost up to mbps in the file copy dialog for a short while but then tapers off to a halt, all the while network stats still show the same 35mbps peak and then dropping to zero and fluctuating. Try to find a different driver from a third party. Brand Representative for StarWind. Bad news: Microsoft banned our design monolithic SCSI port, undocumented one they use for own storage drivers but for third-parties they promote completely different port-miniport design from certification so we can't logo our initiator One big reason we moved it to "Legacy" tools and don't really support anymore.
So OP is encouraged to give it a try but we can't help if something goes wrong. My experience has been that sharing the regular network with iSCSI give horrible results. I've tried a few of them, and they never give great performance.
You'll have to pay for it, too, so you'll have to decide if the price is worth the performance. The initiators in WS R2 and are much better than prior iterations, though some 3rd party solutions can still perform better. I feel like there's a piece of information about the way the NAS is being used that we're missing. That's what I get for quoting my boss. He's a super strong tech, but the number of times it has led to me inserting both feet into my mouth Based on some terribly designed testing we've done, I've seen iSCSI perform acceptably with Synology units with 2 switches in between and on a flat network.
But it was a single thick-provisioned LUN on top of the whole array. Not a lot to break. What are you using on the NAS side? Both servers running R2.
As a side note, I just went and tried creating a iSCSI target on my one server and connecting on the second and vice versa and those were able to saturate the gigabit connection with ease and consistently.If i mount the iSCSI target on my windows client, the speeds are very good so it's not the server software. Do I have to enable anything else on my ESXi box to make it work fast? Even if this is inaccurate, the access is too slow to be used. We're talking minutes here to scan the target for devices and even more minutes to bring up a virtual machine stored on the iSCSI datastore Sounds like this kind of issue.
How do I use prefmon? Why does it say this? My iSCSI target is on It's an informational message only. Does the iSCSI target have the ability to define target portal groups, you will need to do that in order to tell the initiator what IP it should connect to. Otherwise it will try both IP's.
I'm not sure if this is the cause of my problems or thats just a misconfiguration due to me testing the speed on my vista client eralier on I was having problems with esxi before this.
It's not likely to be the root of the issue. SCSI reservation conflicts will occur when the target returns a unable to lock resource status for the requested block reservation sbd cmd. Do you have more than one iSCSI initiator connected e.What is ISCSI? And why is it mentioned in NAS all the time
Hi folks. It's VERY slow. Like, beyond useable slow we're talking 0. Your help is appreciated, Cheers. I have the same question Show 0 Likes 0. This content has been marked as final. Show 18 replies. How are you measuring the speed? Use perfmon to examine the network error stats. How are the interfaces wired?
Any ideas?While Fibre Channel provides enterprises with high-speed transfer rates, is the amount it offers a bit overkill? Fibre Channel storage has long been considered the gold standard when it comes to common technologies to deploy to support an organization's computing environment.
This environment consists of storage arrays that are outfitted with Fibre Channel connectivity. These arrays are then connected to a dedicated storage networking environment that is comprised of, surprisingly enough, Fibre Channel switches.
At the other end of the connection lie the individual servers, each of which is equipped with a Fibre Channel host bus adapter HBAwhich connects the host systems to the same Fibre Channel switches, handily completing the communications loop.
Over the years, speeds have continued to increase as storage performance demands have accelerated. For years, Fibre Channel and other storage environments relied solely on spinning disks to store data.
These disks can only push so much traffic through the communications fabric and it takes a whole lot of disks to even come close to saturating fast Fibre Channel links. With the rise of solid state storage, though, throughput opportunities are much greater and organizations are leveraging this class of storage at many different points in the storage environment, including right in the array.
Most notably, Fibre Channel is purpose-built to support storage and that's all it does. Fibre Channel environments generally enjoy low latency storage access, at least where the communications fabric is concerned. Fibre Channel HBAs for servers and Fibre Channel switches are not inexpensive hardware devices to procure and this communications fabric alone will add tens of thousands of dollars of cost to a storage purchase.
Further, because it's a unique communications fabric, FIbre Channel requires a specialized skill set that can tune the technology and configure it using its own administrative schemes. There are two primary reasons that iSCSI storage environments hit the market by storm.
Ethernet is a common standard and is already pervasive in the enterprise. Leveraging this technology avoided the need to build teams of people with specialized Fibre Channel skills.
Second, because of this reliance on an existing ubiquitous technology, iSCSI is much less expensive than Fibre Channel -- by wide margin. General thinking used to dictate that Fibre Channel was for the enterprise while iSCSI was for smaller organizations, but that mindset has gone the way of the dodo. Today, even large enterprises are relying on 10GB iSCSI storage connections to meet the needs of even the most demanding workloads.
Today's data center Ethernet technologies rival Fibre Channel when it comes to being all but lossless. As such, there is less of an underlying performance differentiation than there used to be in the past. Reality Strikes It's easy to compare speeds and feeds and attempt to determine which is faster.
But, in reality, it really doesn't matter except for the largest organizations and those organizations that are pushing their storage throughput to the limits. In the real world, the link between the storage and the servers is rarely the point of contention when it comes to performance.
So, the bottom line is this: Throughout speed is important, but it's rarely the metric that has a negative impact on storage performance. Scott D. Lowe is the founder and managing consultant of The Groupa strategic and tactical IT consulting firm based in the Midwest.
Scott has been in the IT field for close to 20 years and spent 10 of those years in filling the CIO role for various organizations.
He's also either authored or co-authored four books and is the creator of 10 video training courses for TrainSignal. By Scott D. About the Author Scott D.This is the same with FC and Ethernet.
Bandwidth has an impact on storage performance when large requests are being processed. In this case, most of the work is spent transferring the data over the network making bandwidth the critical path.
However, for smaller read and write requests the storage system spends more time accessing data making the CPU, cache memory, bus speeds and hard drives more important to overall application performance. Unless you have a bandwidth intensive application e. In fact, an iSCSI storage system can actually outperform a FC-based product depending on other, more important factors than bandwidth -- including the number of processors, host ports, cache memory and disk drives and how wide they can be striped.
The slowest component of the storage performance chain is the hard disk drives. It takes a hard disk drive much longer, sometimes several thousands-percent longer, to access data in a storage system than the electronic components like processors, bus and memory.
This is followed by long, mechanical access times waiting for the drive to move the actuator, referred to as the seek process.
The seek process is by far the slowest part of storage performance. The actuator then has to spin to the data that's been requested, which is another long mechanical process that creates latency.
Next, the data is transferred from the drive to the CPU and a status handshake is performed to terminate the request. Traditional storage systems are typically limited in the number of drives across which they can stripe data. Many traditional storage systems can only stripe up to 16 drives, while more advanced products can stripe across hundreds of drives.
Striping data across many drives increases performance and essentially eliminates the need for tuning performance and determining hot spots. In ESG Lab head-to-head testing, we configured a storage system using traditional striping methods and another one using wide striping.
ESG Lab used the same workloads to compare the performance of the traditionally configured system and that of a system using a wide stripe group of 48 drives.
The stripe group of 48 drives significantly outperformed the traditional method. The architecture of the storage system, the speed and number of processors, the amount of memory and the intelligence of its caching algorithms, the speed the disk drives and number of drives in a stripe group, the number of host ports and the backend interconnect all play a major role in performance.
I recommend that you evaluate the storage system based on all of the above criteria. It is the storage system itself that will make a bigger difference. The speed of iSCSI is not the issue. Please check the box if you want to proceed. Fidelma Russo, CTO at Iron Mountain, addresses data needs associated with digital transformation and how using that data will The COVID pandemic is adversely affecting businesses worldwide, but data science can help you solve immediate problems and New research by Cisco Talos shows popular fingerprint scanning technology can be defeated by lifting actual fingerprints and Here are common issues IT teams of all sizes -- like those at Zoom When faced with disaster response, wireless network professionals can volunteer their Wi-Fi skills and advise friends and family Server hardware has consistently evolved since the s.
What are some alternatives, besides fiber channel to remove the network bottleneck? We are aware of enabling jumbo frames, and will give that a try, anything else. What sort of performance should we expect using a single gigabit connection per hypervisor?
Hence, don't expect to see that going to each VM server. I've managed a SAN that used these sort of drives, and quite frankly I'd spend the extra money on decent drives if I was going to do it again. The easiest way to increase that is likely to put more NICs in both the storage server and the hypervisors and use port aggregation. No it doesn't. For a start there are protocol overheads.
See: Protocol Overhead. Now, adding iSCSI. It appears as well that iSCSI add's a 48 byte header. So with an MTUwhat's left is bytes.
That assumes a perfect transfer with the whole frame being filled and no dropped packets. In reality I'd expect you to drop below that especially if other users are hitting the target machine. LACP won't help. MPIO is the only way to increase bandwidth. Sign up to join this community. The best answers are voted up and rise to the top.
Home Questions Tags Users Unanswered.
Asked 8 years, 8 months ago. Active 2 years, 10 months ago. Viewed 37k times. Justin Justin 4, 16 16 gold badges 47 47 silver badges 74 74 bronze badges. Active Oldest Votes.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 bytes or higher -- transferring far more data in each packet while requiring less overhead. Switch port performance can also be enhanced by eliminating "oversubscription. Rather than allowing multiple devices to compete for one switch port, establish a limit of one device per port. It's important to consider the performance of your iSCSI initiator server-side software.
As with any device driver, the quality and integrity of your iSCSI initiator software can vary dramatically depending on the vendor, their experience in the iSCSI market, and the maturity of their iSCSI product -- some initiators simply work better than others.
It may be worthwhile to test the performance and robustness of several iSCSI initiators before deciding on the best initiator. TOE cards and other hardware devices include their own initiator firmware, eliminating the need for separate initiator software. This not only impairs SAN performance, but also creates a potential security risk since storage data is accessible on the user LAN. Check out the entire iSCSI vs. FC handbook. Please check the box if you want to proceed. Fidelma Russo, CTO at Iron Mountain, addresses data needs associated with digital transformation and how using that data will The COVID pandemic is adversely affecting businesses worldwide, but data science can help you solve immediate problems and New research by Cisco Talos shows popular fingerprint scanning technology can be defeated by lifting actual fingerprints and Here are common issues IT teams of all sizes -- like those at Zoom When faced with disaster response, wireless network professionals can volunteer their Wi-Fi skills and advise friends and family Server hardware has consistently evolved since the s.
CPUs have evolved to meet ever-increasing technology demands. We look at the way performance and power characteristics have The quantum computing industry is entering a new era.
How will 10 GbE impact iSCSI speed?
IBM's Bob Sutor discusses the technology's importance and how his latest On-site monitoring centers come under stress when it's necessary for most workers to telecommute. Here are key points to include Consultants detail 10 to-do items for data management teams looking to create a data strategy to help their organization use data Technology to rapidly correlate and connect disparate data sets in a knowledge graph is being used by German researchers andMany technologies originally intended for the enterprise end up trickling down into the consumer market at some point.
Some of these technologies ethernet or virtualization, for instance are more practical than others; but if businesses find a use for a specific piece of technology, then chances are good that consumers can benefit from it as well. Such is the case with iSCSI. SCSI sans i has long served to connect a variety of peripherals to computer systems, but most commonly it appears in storage devices, such as hard drives or tape-backup drives.
Judging from that description, you may be wondering how iSCSI differs from any other network share with a mapped drive letter. On many levels, the end results are similar. With iSCSI, though, the attached volume appears to the operating system as a locally attached, block storage device that you can format with the file system of your choice. In addition, fewer layers of abstraction separate an iSCSI volume and your PC, which can result in increased performance.
Ready to get your hands dirty with some hardware? If you wish to use iSCSI, there are two main requirements: a network-attached storage device or server with a volume that can be configured as an iSCSI target, and an iSCSI initiator, which allows a system to connect to the target.
I've already touched on some of the benefits of using iSCSI. This flexibility is great for small businesses because many programs cannot run over shared networks, even if you're using mapped drive letters; iSCSI works around that issue.
For some workloads, iSCSI may also offer better performance. Although iSCSI improves PC performance in the enterprise by allowing large storage arrays to connect to client systems without the need for custom hardware or cabling which can result in a huge cost savingsI'm going to focus on average consumers and desktop systems here. To prove that iSCSI can enhance your PC's performance, we ran some benchmarks on a testing unit; I'll show you the results on the next page.
Note, however, that using iSCSI has some drawbacks. While setup is not terribly difficult, configuring an iSCSI target and initiator is more involved than simply browsing to a shared network resource.
Also, only one initiator should be connected to the iSCSI target at a time, to prevent possible data loss or corruption.
Subscribe to RSS
In addition, assuming that you use a fast server and drives, performance may be limited by your network connection speed. A gigabit network connection or better is the optimal choice; with slower network connections, the potential benefits of iSCSI may be nullified. The steps should be similar for other devices and servers as well. To see how everything works, click on each screenshot for a larger version.
We used RAID 1 for redundancy with two 2TB drives, and split our setup right down the middle--dedicating half of the usable capacity to an EXT4 data share while leaving the other half unused. We would later configure the unused space for iSCSI purposes. When the formatting process is complete depending on your drive setup, it could take hoursyou can then configure the unused space as an iSCSI target.
Note that if you reserved all of the available storage space for iSCSI, you will have no need to format the array at this point. Then we clicked the Add button under the 'iSCSI target' tab; a new window popped up, in which we had to set the desired size of the iSCSI target, enable it, and give it a name. At this point, you can also enable CHAP Challenge Handshake Authentication Protocol authentication if you wish to add a layer of security, but we chose not to.