ISCSI SAN with esxi 5 large volume vs multuple smaller volumes
we recently purchased a new equalogic ISCSI SAN. we plan to use it for our vmware infra which our 7 hosts are using about 7TB spread over their local storage.
my question is we would like to connect our 7 hosts (approx 70 vm's) to the san but are unsure if it is better to create 1 big volume lets say 12TB with one datastore on it or multiple smaller volumes with multiple datastores.
help is appreciated
my question is we would like to connect our 7 hosts (approx 70 vm's) to the san but are unsure if it is better to create 1 big volume lets say 12TB with one datastore on it or multiple smaller volumes with multiple datastores.
help is appreciated
We prefer to create smaller LUNs, that store all your VMs on a single large LUN, for LUN contentions, and also to prevent disasters, "all eggs in one basket".
We usually carve out LUNs between 500-800GB for VMs, unless there is a requirement for a very large virtual disk, which requires a large LUN.
We usually carve out LUNs between 500-800GB for VMs, unless there is a requirement for a very large virtual disk, which requires a large LUN.
you will need a very good connection for that many vm's too wheter its 1 large lun or several smaller luns
Some of my EE Articles I've written, with Walkthroughs and Screenshots to help you configure ESXi.
HOW TO: Enable Jumbo Frames on a VMware vSphere Hypervisor (ESXi 5.0) host server using the VMware vSphere Client
HOW TO: Add an iSCSI Software Adaptor and Create an iSCSI Multipath Network in VMware vSphere Hypervisor ESXi 4.1
HOW TO: Add an iSCSI Software Adaptor and Create an iSCSI Multipath Network in VMware vSphere Hypervisor ESXi 5.0
HOW TO: Enable Jumbo Frames on a VMware vSphere Hypervisor (ESXi 5.0) host server using the VMware vSphere Client
HOW TO: Add an iSCSI Software Adaptor and Create an iSCSI Multipath Network in VMware vSphere Hypervisor ESXi 4.1
HOW TO: Add an iSCSI Software Adaptor and Create an iSCSI Multipath Network in VMware vSphere Hypervisor ESXi 5.0
Multiple luns is adviced for performance and data corruption.
If the san also has multple interfaces you can setup also multiple iscsi paths that increases the bandwith.
Disksize is not really the limit it is more the expected io from the servers. One server with just 100GB can pull that much io that other servers are gettings problems.
And an other lun with 800Gb on servers is almost doing nothing.
Keep these things in mind and you will do well.
If the san also has multple interfaces you can setup also multiple iscsi paths that increases the bandwith.
Disksize is not really the limit it is more the expected io from the servers. One server with just 100GB can pull that much io that other servers are gettings problems.
And an other lun with 800Gb on servers is almost doing nothing.
Keep these things in mind and you will do well.
Use smaller LUNs because the EqualLogic arrays are not as space friendly as you would like. Between replication reserve and snapshots, I get about 35-40% of the array capacity available for LUNs. If you have really large LUNs, you may not have enough free space to make a snapshot, clone a volume, or perform other desired activities. If you have smaller LUNs, you can also have different policies for the LUNs, such as some LUNS getting a snapshot daily, others weekly, and some not at all. I like to keep the pagefiles of my VMs on their own separate LUN. That LUN doesn't get replicated nor snapshot, which keeps down the change rate onmy real data volumes, which reduces the amount of snapshot space required.
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