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39

Fibre Channel switches usually connect clients to storage. FC is a protocol that is designed explicitly to transport SCSI commands. In fact, the Fibre Channel protocol is a direct extension of the SCSI protocol. All SCSI commands have a FC equivalent, and FC has a few extra ones that allow for networking. Assuming you have all the physics of your FC network ...


34

Something everyone carries around with them, a camera phone, can be a massive help. Even if the light is so faint that you can barely make it out, you should be able to tell the difference with a camera phone. Here's an example of a rx cable (with no light coming from it): Here's an example of a tx cable (with light coming from it): It's really ...


16

This term is used most commonly in reference to how SAN storage volumes get connected to the servers that they're assigned to. For instance, with a multipath fibre channel setup, there would be redundant fiber paths between the SAN and the server, with each path going through different FC switches, connecting to different FC cards, etc. This way, if any ...


12

How much storage do you need? If you want something in the 10's to 100's of Terabytes you could look at the Sun X4540 (Thumper). Solaris comes with an iSCSI target if you need block level storage or it can be used as a NAS with NFS or Samba. For those not familiar with Sun's Thumper, it's a 4U 2-socket Opteron box with 48 SATA disks. You can have up to ...


11

FCoE doesn't run over regular Ethernet though, it requires Data Centre Ethernet/Bridging - an evolution of Ethernet that is only current supported on a very limited number of, typically high-end, switches such as Cisco's Nexus range. THIS is a great, and surprisingly short, book that would pretty much tell you everything you'd need to know about the subject ...


9

Orange cable meets the OM2 standard. Aqua meets OM3 or OM4 standards (usually OM3). Yellow is singlemode cable. The OM standards are backward compatible (for the most part; OM1 was defined to be 62.5/125 size; OM2+ are 50/125; but not all manufacturers followed this, just be sure to get the size that matches your equipment or you'll experience some ...


9

In addition to ErikA's excellent response, multipath io (MPIO) not only provides a redundancy enhancement, but also a performance enhancement if both/multiple paths are utilized.


8

It's a hard disk with a FC interface. Nope, you probably can't just arbitrarily replace one of them with a disk with a different interface, and different IO characteristics, especially in a storage array. But ask your vendor to be certain, or consult their documentation! And, spend 30 seconds on Google, too.


7

Depends on your definition of "Cheap". But you could look at HP LeftHand Starter SANs. It's an all iSCSI solution but provides better performance the more you scale it, uses standard servers for the hardware, has solutions in SATA and SAS varieties to fit your budget and performance needs, and is supported by a global, good customer service, company. The ...


7

Mainly you want to make sure your VM's will be OK with no disk IO. Installing the VMware tools will take care of this with 4.x and newer. You also want to set the right settings on your ESX hosts related to timeouts, these are detailed on the netapp site in TR-3749 Really it does not matter which protocol you are using for cluster fail overs since the ...


6

I do not see any reason to do this nowadays. You have modern ethernet NICs with high bandwidth and throughput. Also you do not introduce all kind of inflexibilities introduced with FC and IPFC. Some of them: You can't aggregate FC HBAs -> combine both 10GbE and get 20GbE. You can have them active/standby or use both active/active and get 5Gbps on each. ...


6

Yes it's possible (it's RFC2625) , I did this ONCE to get me out of a major problem I was having at a remote site and although it worked well enough to allow me to transfer the driver file that had me locked out of the box in all other ways I can't say I'd recommend it. Sure it'll be fast and reliable but it was crazy complex to setup and maintain so I'd ...


6

You should probably just use a FC SAN; if you have FC Storage already, you can grab an FC Switch and FC HBAs for the host servers; that will be enough to get a simple FC SAN going. You can use a server to act as a FC-iSCSI gateway; software like Starwind or SanMelody run on Windows; or most Linux distros come with iSCSI Target software. Handling the SAN IO ...


6

sorry for the delay. Had a look at what you've got and what you want to achieve, I had a few thoughts, here's a nice picture first... There seems no point using an 8Gbps link between sites just now - the reason is that you're constrained by the 4Gbps ports on the remote 4400, you’ve got a stable 4Gbps already plus the available bandwidth is much higher ...


6

SCST -- is a generic SCSI target subsystem for Linux (SCST) is an alternative implementation of a SCSI target subsystem for Linux. It provides unified, consistent interface between SCSI target drivers and Linux kernel as well as between Linux kernel and storage backend handlers, connecting target drivers with real or emulated storage backend. SCST allows ...


6

That is possible. It's called IPFC and RFC 2625 specifies it. You have to have an TCP/IP stack for your HBA. Tell more details, which HBAs and Switches etc.


6

If you have a single port on each switch that's logging in as a loop port, you need to address this. The first thing I'd do is try unplugging it and plugging it back in. If it still shows up as a loop port when it relogs back into the fabric, take a look at hard-coding the port to be an F port. I found instructions here. Be prepared that if there's some ...


5

If you have a choice, I'd recommend an HP MSA2040 SAS unit if you only plan to connect to one server. It's a simpler and more effective connection option. Otherwise, this is probably the wrong product for you. Please read the HP StorageWorks MSA 2040 QuickSpecs guide here. If you wish to use fiber channel, you have two options: 8Gb and 16Gb SFPs. The MSA ...


5

There a lot of determining factors that go into the performance feeling here. One tweak you might consider is setting up Jumbo Frames. Scott Lowe has a recent blog post here that shows some of what he did to achieve this. You mention that the guests will be running low CPU load - those are always great candidates for virtualization - but the difference ...


5

Ahh, haven't got enough reputation points to leave comments yet, so it's a seperate post I'm afraid. With regard to the HP Lefthand pricing, a good site to grab the pricing on the Lefthand kit without calling HP is the StorageMojo, the StorageMojo also has list prices for most other manufacturers. You're looking at about £40k for a 2 node setup with a ...


5

Point-to-point is the most self-explanatory, and the usual way of connecting just two devices together so they can communicate. Loop-mode is a way of building a fibre-channel network without using an FC switch. It's analogous to a token-ring network, in that each device in the network forms part of a ring, or loop. I've never seen it used though - the only ...


4

But which application-layer protocol do the clients use in the LAN to communicate with the servers? Is the data simply transferred via ethernet as well? Clients don't care how the storage is presented to the servers. If it's FCP, iSCSI, or whatever on the server, it's just a block device to the server and can be presented to the clients however you ...


4

Would this be an acceptable production solution? No. It would not. You do say that you'd like to "experiment with iSCSI." It is fine for experimentation. I would be using the server like a ISCSI gateway. But I wouldn't want to use Window's horrendous storage pools\RAID solution I would just want to pass clients straight through to the LUNs I served ...


4

FC doesn't use LAG to achieve link redundancy or aggregation. It uses MultiPath IO (MPIO) to establish multiple logical communications channels and presents them to the storage subsystem as a single device.


4

At the beginning host knows WWNN and WWPN. Well, forget WWNN. WWNN, theoretically, should be the same on all ports of all HBAs of a computer, but this is rarely the case. Usually it is the same on one HBA, but I've seen a case of multiport HBA with multiple WWNNs. So it's a bit of a mess. Upon logging to fabric (FLOGI/PLOGI), host gets to know its P_ID ...


4

Ok, I guess I need to post an answer. In one word it is: insist. The problem is not resolved 100% to my liking, as we still have one fabric with 1 (one) CRC error sporadically. The other one is clean. But I can live with that. In any case we won't continue to use the CWDM units for a very long time, but rather switch to a passive DWDM multiplexer next year ...


4

So you have a single FC LUN presented to both a physical machine and to a VM and you want to use ext3 - is that right? If so then you need to learn about the difference between block-level and file-level sharing - and quickly, as you've irretrievably corrupted this LUN already. You have two machines (whether they're physicals or VMs is irrelevant) that ...


4

Fibre channel is generally done through a switch. That said, direct connect is supported, but usually between targets and initiators. Initiators are server HBAs, targets are disk drives (or tapes). I don't know of any software you could run in windows that would allow a server to present its HBA as a target. What you're trying to do is definitely supported ...


4

No, the PMC PM8032 is an FC-only controller, it doesn't handle FCoE sorry. FC and FCoE are very different at the L1 and 2 levels.


4

Can optical fibre communication links be used for a length of 100km as well as 100000km without having to change sender and receiver equipment? In short, no. Any fiber run of decent length is going to require specialized high-power laser optics on both ends as well as some sort of in-line amplification. These days, EDFAs are typically used on very ...



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