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8/6/2019 SAN VS DAS VS NAS http://slidepdf.com/reader/full/san-vs-das-vs-nas 1/1 DAS Vs SAN Vs NAS Something that is making me very angry with the current project I’m on is the difference between DAS, NAS, and SAN technologies. The worst is that I’m working with these people on a specific thing not related to storage infrastructure, but instead development architecture and the people that are dealing with the storage infrastructure are the people that don’t know what the hell their talking about. In particular, the hosting provider that does all of the storage infrastructure work for us doesn’t know what the differences are. Oh, and don’t get me started on a VMware paper that we had that didn’t know the difference either. It just drives me nuts. For those of you keeping score, I’m going to outline this out. DAS = Direct Attached Storage. These are disks that are physically located in your host machine. NAS = Network Attached Storage. NAS is file based. For example a CIFS or NFS share. This is typically TCP/IP based access. The NAS device “owns” the data on it. That is, the NAS device administers the data. For example, you connect to a NAS device from a windows machine by accessing \\servername\share. SAN = Storage Area Network. SAN is block based. This is when LUNs (logical unit numbers) are involved on a host. The host “owns” the data. The host is in charge of the partition, formating, and access to the LUN. You can access a SAN via two protocols: iSCSI (TCP/IP) and/or Fiber Channel (FC). I’m so sick of seeing people talk about iSCSI NAS. There’s no such thing because in a NAS scenario you are sending CIFS or NFS protocols over TCP/IP while in a SAN solution you’re sending SCSI protocols over TCP/IP. Huge difference. And yes, you can have a device that serves both NAS and SAN from one filer. This is called Unified Storage. All NetApp devices can do this. WHAT IS SAN? SAN or storage area network is a high-speed network of shared storage devices ,thier controllers and monitoring software.A SAN system consists of storage elements, storage devices, computer systems, appliances, plus all control software, communicating over a network. A network whose primary purpose is the transfer of data between computer systems and storage elements. A SAN consists of a communication infrastructure, which provides physical connections, and a management layer, which organizes the connections, storage elements, and computer systems so that data transfer is secure and robust. The term SAN is usually identified with block I/O services rather than file access services.

SAN VS DAS VS NAS

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8/6/2019 SAN VS DAS VS NAS

http://slidepdf.com/reader/full/san-vs-das-vs-nas 1/1

DAS Vs SAN Vs NAS

Something that is making me very angry with the current project I’m on is the differencebetween DAS, NAS, and SAN technologies. The worst is that I’m working with these peopleon a specific thing not related to storage infrastructure, but instead developmentarchitecture and the people that are dealing with the storage infrastructure are the people

that don’t know what the hell their talking about. In particular, the hosting provider thatdoes all of the storage infrastructure work for us doesn’t know what the differences are. Oh,and don’t get me started on a VMware paper that we had that didn’t know the differenceeither. It just drives me nuts.

For those of you keeping score, I’m going to outline this out.

DAS = Direct Attached Storage. These are disks that are physically located in your hostmachine.

NAS = Network Attached Storage. NAS is file based. For example a CIFS or NFS share. Thisis typically TCP/IP based access. The NAS device “owns” the data on it. That is, the NASdevice administers the data. For example, you connect to a NAS device from a windowsmachine by accessing \\servername\share.

SAN = Storage Area Network. SAN is block based. This is when LUNs (logical unit numbers)are involved on a host. The host “owns” the data. The host is in charge of the partition,formating, and access to the LUN. You can access a SAN via two protocols: iSCSI (TCP/IP)and/or Fiber Channel (FC).

I’m so sick of seeing people talk about iSCSI NAS. There’s no such thing because in a NASscenario you are sending CIFS or NFS protocols over TCP/IP while in a SAN solution you’resending SCSI protocols over TCP/IP. Huge difference.

And yes, you can have a device that serves both NAS and SAN from one filer. This is calledUnified Storage. All NetApp devices can do this.

WHAT IS SAN?

SAN or storage area network is a high-speed network of shared storage devices,thier controllers and monitoring software.A SAN system consists of storage

elements, storage devices, computer systems, appliances, plus all control software,communicating over a network.

A network whose primary purpose is the transfer of data between computer

systems and storage elements. A SAN consists of a communication infrastructure,which provides physical connections, and a management layer, which organizes the

connections, storage elements, and computer systems so that data transfer issecure and robust. The term SAN is usually identified with block I/O services ratherthan file access services.