Welcome to my EMC CLARiiON blog central. Here, I will share my knowledge of the Clariions, as well as any new information that I come across in my teachings.
Tuesday, February 12, 2008
Setting the Alignment Offset
12 comments:
Anonymous
said...
I was able to follow your directions on server 2003 quite easily, but I was asked to convert the basic disk to a dynamic disk and this procedure does not seem to work for a dynamic disk. Is there a way to do this on a dynamic disk? Diskpart shows 3 new partitions when it is a dynamic disk.
sorry...this is only for a basic disk in windows...we use basic disks for a couple of reasons...1. you can grow a basic disk on a host after you have created a metalun in navisphere on that lun...and use diskpart to expand the basic disk.... 2. snapview is not happy with dynamic disks at all... 3. i have heard that even from microsoft people not to use a dynamic disk
Hi. The described procedure for Linux server is only for vmware VMFS file system (ESX servers). To make the procedure a little bit "universal", I modified it, with the most common Linux partition types, as follows:
Setting the Alignment Offset for Linux Servers
The following procedure assumes the creation of a new partition on a new unpartitioned device. If you already have a partition created, it should be removed first. The procedure will erase all of the data on the selected partition.
Execute the following steps to align partitions on a Linux system, assuming single disk full partition:
1. On service console, execute "fdisk /dev/sdX" (or "fdisk /dev/emcpowerX" for clariion systems), where X is the device on which you would like to create the new partition (a, b, c, etc). 2. Type "n" to create a new partition 3. Type "p" to create a primary partition 4. Type "1" to create partition #1 5. Select the defaults to use the full disk. 6. Type "t" to change partition type 7. Type "1" to select partition #1 8. Depending on your Linux environment and need: type "83" to set type to Linux partition, or type "82" to set type to Linux swap, or type "8e" to set type to Linux LVM, or type "fb" to set type to VMFS (vmware file system). For other partition types, type "L" to display the list of codes. 9. Type "x" to get into the expert mode 10. Type "b" to specify the starting block of partitions 11. Type "1" to select partition #1 12. Type "128" to make partition to align on 64KB boundary (block No. 128) 13. Type "w" to write new partition information to disk.
We are bringing up a VMWare ESXi host and attaching it to our Clariion. The version of ESXi is 3.5. The ESXi doesn't have a command line interface like the ESX does. And I think I read a blurb somewhere that stated with ESX 3.5, VMWare was going to take care of the alignment issue. Do you know of a way to double check this on a ESXi host?
On Linux servers if we are using Logical Volume Manager to manage our disks, how does this offset be configured? I thought that LVMs align the offset correctly by default. Is that a correct statement?
12 comments:
I was able to follow your directions on server 2003 quite easily, but I was asked to convert the basic disk to a dynamic disk and this procedure does not seem to work for a dynamic disk. Is there a way to do this on a dynamic disk? Diskpart shows 3 new partitions when it is a dynamic disk.
sorry...this is only for a basic disk in windows...we use basic disks for a couple of reasons...1. you can grow a basic disk on a host after you have created a metalun in navisphere on that lun...and use diskpart to expand the basic disk.... 2. snapview is not happy with dynamic disks at all... 3. i have heard that even from microsoft people not to use a dynamic disk
OK, thanks for the info.
I had to use gpt as my my shares are over 2Tb apiece but other then that it went well.
So if I have to use GPT, will there be any performance penalty other than snapview issue, since it cannot be offset by 64Kb?
Alighment offset only applies to stripes sets, correct? It applies to RAID 0, 5 and 1+0 but not RAID 1? Thanks much for your very helpful posts!
Hi. The described procedure for Linux server is only for vmware VMFS file system (ESX servers). To make the procedure a little bit "universal", I modified it, with the most common Linux partition types, as follows:
Setting the Alignment Offset for Linux Servers
The following procedure assumes the creation of a new partition on a new unpartitioned device. If you already have a partition created, it should be removed first. The procedure will erase all of the data on the selected partition.
Execute the following steps to align partitions on a Linux system, assuming single disk full partition:
1. On service console, execute "fdisk /dev/sdX" (or "fdisk /dev/emcpowerX" for clariion systems), where X is the device on which you would like to create the new partition (a, b, c, etc).
2. Type "n" to create a new partition
3. Type "p" to create a primary partition
4. Type "1" to create partition #1
5. Select the defaults to use the full disk.
6. Type "t" to change partition type
7. Type "1" to select partition #1
8. Depending on your Linux environment and need: type "83" to set type to Linux partition, or type "82" to set type to Linux swap, or type "8e" to set type to Linux LVM, or type "fb" to set type to VMFS (vmware file system). For other partition types, type "L" to display the list of codes.
9. Type "x" to get into the expert mode
10. Type "b" to specify the starting block of partitions
11. Type "1" to select partition #1
12. Type "128" to make partition to align on 64KB boundary (block No. 128)
13. Type "w" to write new partition information to disk.
Hope this helps.
http://tipstricksandmore.blogspot.com
We are bringing up a VMWare ESXi host and attaching it to our Clariion. The version of ESXi is 3.5. The ESXi doesn't have a command line interface like the ESX does. And I think I read a blurb somewhere that stated with ESX 3.5, VMWare was going to take care of the alignment issue. Do you know of a way to double check this on a ESXi host?
Scott
On Linux servers if we are using Logical Volume Manager to manage our disks, how does this offset be configured? I thought that LVMs align the offset correctly by default. Is that a correct statement?
I should have looked further in this blog. Looks like this question (about LVM) has been answered elsewhere. Please ignore my question.
Can someone reference an EMC Document stating that disk alignment isn't required for LVM volumes?
Hi, well be sensible, well-all described
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