VM /ETC

Archive for the ‘SAN’ Category

Earlier this week the VMware VI Team Blog reported that as of ESX version 3.5 Update 1 Storage VMotion is now officially supported for iSCSI SANs. This means that administrators can reorganize virtual machines without down time in order to match any storage needs. The Storage VMotion and 10Gb Ethernet support for iSCSI SAN’s post explains:

“Although Storage VMotion is designed to work with any type of storage, it was initially supported only with Fibre Channel SANs. As of Update 1, Storage VMotion is supported with iSCSI SAN’s for moving virtual machine disk files in the following scenarios:

- From iSCSI SANs to other iSCSI SANs

- From iSCSI SANs to FibreChannel SANs

- From FibreChannel SANs to iSCSI SANs

In addition, we now support the use of 10Gb Ethernet for iSCSI in a VMware Infrastructure environment.”

In my experience Storage VMotion has worked great, but be careful with VMs that have higher I/O utilizations. Read the rest of this entry »

Lately, I have had several clients and peers ask me how to get disk usage and performance statistics from their current virtual infrastructure of ESX hosts and virtual machines . Some needed data for planning and sizing a new SAN, while others needed statistics for upgrading, adding more disks, or for optimizing multi path and VMFS performance. In one case the customer was trouble shooting poor VM performance issues. Regardless of the objectives there are some built in tools in both VirtualCenter and ESX server that can get this information for you. This post explains 2 native methods:

• Using the VI Cleint to access the Performance data in VirtualCenter
• Using esxtop from the ESX Service Console

I have included plenty of screenshots. As always, click on them for larger views. The rest of this post is in an outline format, but should be easy enough to follow. Read the rest of this entry »

Chad Sakac has a great post on his Virtual Geek blog titled The Case For And Against Stretched ESX Clusters. In this post Chad discusses the possibilities of configuring ESX Clusters between 2 different physical data centers. That is, spanning the SAN across a wide area network so that VMs can be vmotioned between sites. The concept is a frequently discussed desire of many administrators, and Chad brings to light some great points for and against this design with specific configuration details about making it work with VMware ESX.

For example, the post explores several options: Read the rest of this entry »

Michael Healey over at InformationWeek has written an article that demonstrates real world pricing scenarios comparing the cost of a SAN with replacing physical servers and local RAID 5 storage. ROI Analysis: Virtualization uses an example of 10 physical servers at their “end of life” and focuses on hard cost savings that will even make sense to the CIO. Read the entire article, but here’s the results:

“Scenarios under consideration:

1. Replace with 10 traditional servers: Ten HP ML350 boxes with mirrored boot drives and RAID 5 storage–$62,100.

2. Virtualize 10 servers using three physical servers with local storage: Three HP ML350s with more memory and RAID 5 storage running VMware ESX (licenses included)–$49,300.

3. Same virtualized servers in a cluster that boots to a 1-TB SAN: Three HP ML350s with more memory, boot drives, and VMware Enterprise, plus a Hitachi SAN for storage–$52,730.”

As Michael points out, migrating to virtual infrastructure and spending $3500 extra for a SAN (scenario 2 versus 3) are options that should make sense to even the most cost conscious IT departments!

Based on best practices, this post is a “formula” for planning and sizing SAN storage for maximum VMFS performance. This is intended to be for all protocols where VMFS volumes are utilized ( FC, iSCSI ) and conservative enough to allow general sizing estimates while ensuring high performance of the running VMs.

WARNING: The storage design resulting from following these recommendations will not be the most cost effective solution. As storage performance generally requires the most spindles (disks) possible and this formula requires as many dedicated LUNs as possible, the cost for storage will be maximized. More often than not, compromises between performance and cost have to be reached that keep the design within the expected budget.

This post is split into 2 sections. The first section lists the VMFS Maximum Performance Rules while the second section uses a 25 server example to walk through the design rules. Read the rest of this entry »

This post is a supporting post to the discussion earlier this week sparked by Scott Lowe’s tip on avoiding ESX snapshots when using SAN device snapshots. NetApp’s SnapManager for Virtual Infrastructure (SMVI) is discussed as a solution for streamlining the coordination of snapshots between ESX and the SAN. Luckily, Nick Triantos from NetApp joined the discussion on Scott’s blog with some “under the hood” information: Read the rest of this entry »

Avoiding storage array snapshot pitfalls in a VMware environment is an article and tip published by Scott Lowe for Searchvmware.com. Scott discusses the design challenges and implications of combining the snapshot abilities of VMware ESX with the SAN based snapshot features of storage devices. The tip points out that incorrect configuration of VMware ESX with the storage device could lead to inconsistent and unusable images when trying to recover VMs.

“Because these snapshots are not, by default, integrated in any way with VMware ESX Server, we have to perform a few extra steps to ensure consistently reliable and usable storage array snapshots.”

Read all of Scott’s tip at the link to the article above.

My “2 cents” on this is that trying to configure the combination of the two snapshots manually might not Read the rest of this entry »