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What is the difference between NAS and SAN storage?

What does a storage engineer take into account when deciding between NAS or SAN storage?

ITCS user
66 Answers

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Top 5LeaderboardReal User

NAS: cheaper, slower to access, easier to manage
SAN: more expensive, fast access, needs specialist management skillset.

SAN is generally used when you need lots of storage close to computing power.
NAS when you need storage shared by networked users.

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Top 5Real User

There can be MANY things to be considered here, but it can also be simple. As with most IT infrastructure things, there are plenty of variables that might apply in some scenarios and not in others. Given the limited about of information we have to work with, I'd say it mostly boils down to a few things:
(1) Is this data to be accessed and manipulated by a human user, or by another computer (such as an application server or data base server).
(2) Are the files in question large files that are sequentially accessed (video, audio, etc) or are they "small-block RANDOM" in nature - or is it a mix?
(3) Do you have specific network constraints between the storage and the systems accessing it?

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Real User

Depending on Requirements & what workload defined for NAS vs SAN
NAS - Fabric -tcp/ip- File Level -Performance - lower -Scalability - limited -Manageability - easier to manage - Price - less
SAN- Fabric -FC Networks - Block Level -Performance - Higher -Scalability - scale up-scale -out -Manageability - more complex to manage Price -More expensive

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Top 5LeaderboardReal User

First, we should define what we mean by SAN and NAS. The most common and general definition is: SAN is a stack of block access protocols and hardware, and NAS is file-level protocols. So, the choice depends on the task at hand. In my opinion, NAS is easier to manage and maintain if used for virtual machines datastores - NFS for VMware and xen and cifs for Hyper-v. File protocols are also good in sql server clustering (no need in middleware like iSCSI or costly FC SAN infrastructure). For now (end of 2020), file protocols also have faster access speed than FC (32Gb FC vs 100Gb Ethernet or even more via single link). File protocols also have an advantage if you run DECO on your storage - you don't need to run UNMAP on host, which doesn't work in some configurations and needs additional attention and administrator's time. On the other hand, block protocols (SAN) are mature, have a wide install base, and a huge amount of vendors are supported. 

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Top 5LeaderboardReal User

The type of usage has first to be taken into consideration.
Most work can be done on a NAS as disks have grown faster.
However, high performance DB should be on SAN.
In the longerterm, NAS can suffer as some users have the tendency to put DBs there because of the relative ease of use

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Top 5Real User

You will understand clearly having a look at:
https://www.backblaze.com/blog/whats-the-diff-nas-vs-san/> https://www.backblaze.com/blog/whats-the-diff-nas-vs-san/


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