MSA2012i - Redundancy and bandwidth

[meredith shaebanyan]

Flat out it's not feasible to put 50 guests on 6 SATA drives unless they are extremely low IO (like, each vm accessed by a single developer or something like that). Get the SAS drives; they are a lot more expensive, but if you already bough an MSA 2000 and some kind of switching infrastructure to go with it (I use Fibre Channel, but i guess iSCSI might be cheaper) you already spent a lot of money; you are short-changing yourself if you go for the SATA drives.

That being said, if the iSCSI model works the same as the FC model, ports A on controller one and A on controller two are basically the same port; it doesn't give you the option in the SMU to map a LUN through either c1/A or c2/a; you map it through port a, and it's visible through that port regardless of which controller has ownership of the vdisk.

[Alessandro_78]

Thanks patrick, but how can I calculate or set the transfer size?

And after calculating the correct number of disks needed, the bottleneck will be always the ethernet channel.

To all: SATA was just an example. If i'll buy i san, i'll do with SAS disks.

[Patrick Terlisten]

Hello,

it depends on you application. Take a mean value, maybe 16 or 32 KB. If you doing a lot of mail, proxy, news or database think about a transfer size < 16 KB or < 8 KB.

Best regards,
Patrick

[Alessandro_78]

Main application that will be installed on VPS are mail server, web server and logs.

[Patrick Terlisten]

Hello,

then you should calculate with a transfer size of 8 KB.

Best regards,
Patrick

[Alessandro_78]

So 8KB is a good mean value for a standard VPS?
Thank you.

Another question: are there any mean value list for the most common server uses?

Like:
web server, 10KB
mail server, 8KB

etc etc.

[Patrick Terlisten]

Hello,

I think that these are good values for small IOs. It depends on the application. These are only guidelines.

Best regards,
Patrick

PS: Don't forget to assign points to the other members.

[saha_1]

Hi,

I bought a MSA2012i and two servers for virtualisation. Can anyone tell whether servers can be directly connected to MSA2012i storage directly without swithes?

Two ports from each server to each controllers in storage for redundancy.

Thanks.