最後更新: 2019-06-19

目錄

• clone the VMDKs while preserving the thin provisioning
• 為 phyiscal harddisk 建立 vmdk 檔
• Check File Size
• vmdk disk description
• Rename vmdk file
• Check vmdk Consistent
• Troubleshoot

 

---

clone the VMDKs while preserving the thin provisioning

 

Example:

vmkfstools -i "source.vmdk" -d thin "destination.vmdk"

opts:

• -i --clonevirtualdisk srcDisk
• -d --diskformat [zeroedthick|thin|eagerzeroedthick]
• -x --fix [check|repair]
• -v --verbose
• -X --extendvirtualdisk #[gGmMkK]

output:

Destination disk format: VMFS thin-provisioned
Cloning disk 'winsrv2k8.enterprise.201306.vmdk'...
Clone: 10% done.

diskformat

--- VMDK 建立時立即佔用空間 ---

zeroedthick (default)

VM read / write HDD 時才 zeroed out block

eagerzeroedthick

VMDK 建立時立即 zeroed out allocated space

thick

doesn.t zero out any old data that might be present on this allocated space

EagerZeroedThick 及 ZeroedThick

EagerZeroedThick 及 ZeroedThick 在 SSD 上才有功能上的分別

When you delete a VM (or move one)

 -> release space on filesystem, the underlying storage is not told.

     (delete the vmdk so that the space is now free on the VMFS, but not on the physical device)

     (底層要 UNMAP 才 free 出空間)

VM 刪除後立即建立一樣大小的 VM, 會有以下情況:

 - the guest sees it as free

 - VMFS sees it as reserves

 - physical device sees it as fully written to

To release dead storage you either:

    overwrite space with zero (VM use all space)

    release the "dead" space By CLI (UNMAP, 需要在 VM 被刪除後立即執行)

    Delete the physical volume (不可能這樣做, Volume 內有其他 VM)

eagerzeroedthick

When the FlashArray receives zeroes it will not store them on the SSDs.

It instead removes them inline and will return zeroes if those LBAs are read from.

writing zeroes to written space is very much like running UNMAP

------------

FlashArray 廠:

• Dell EMC
• NetApp
• Pure Storage

--- Thin-provisioned virtual disk ---

thin

Unlike with the thick format, space required for the virtual disk is not allocated during creation,

but is supplied, zeroed out, on demand at a later time.

 

---

RDM - 為 phyiscal harddisk 建立 vmdk 檔

 

RDM = Raw Device Mapper

Step1: 查看有什麼 Disk

ls -l /vmfs/devices/disks

lrwxrwxrwx    1 root     root 36 Apr  6 11:33 vml.?2048 -> naa.?2ef1

Step2:

vmkfstools -r /vmfs/devices/disks/DEVICE  ./RDM-DSK.vmdk -a lsilogic

map 的方式

• # Creates a raw disk mapping (virtual compatibility mode)
  --createrdm | -r DEVICE ?.vmdk
• # Creates a passthrough raw disk mapping (physical compatibility mode)
  --createrdmpassthru | -z <device> <map_file>

other settings

• -q --queryrdm
• -a --adaptertype [ buslogic | lsilogic | ide | lsisas | pvscsi ]

virtual v.s. physical mode

Physical mode

specifies minimal SCSI virtualization of the mapped device
=> allowing the greatest flexibility for SAN management software.

The VMkernel passes all SCSI commands to the device, with one exception - "REPORT LUNs"
<= Otherwise, all physical characteristics of the underlying hardware are exposed.

Virtual compatibility mode

VMkernel sends only READ and WRITE to the mapped device.
=> The real hardware characteristics are hidden.
=> more portable across storage hardware than physical mode

 * You cannot map a disk partition as RDM. RDMs require the mapped device to be a whole LUN.

performance:

• For random reads and writes,
    VMFS requires 5 percent more CPU cycles per I/O operation compared to RDM.
• For sequential reads and writes,
    VMFS requires about 8 percent more CPU cycles per I/O operation compared to RDM.

 => RDM 比 vmfs 快 5~8%

 

---

Check File Size

 

du -h server2003sp2

4.9G    server2003sp2

ls -lh server2003sp2/server03sp2-flat.vmdk

-rw-------    1 root     root        80.0G Jul  9 05:05 server2003sp2/server03sp2-flat.vmdk

stat server2003sp2/server03sp2-flat.vmdk

  File: "server2003sp2/server03sp2-flat.vmdk"
  Size: 85899345920     Blocks: 10356736   IO Block: 131072 regular file

Default block size: 512 byte

 

---

vmdk disk description

 

The disk description file or .vmdk, is a metadata file

It contains data that describe the geometric characteristics and size of the disk where the data will be stored.

A virtual disk is made up of two files:

 * File descriptor, its extension is (.vmdk)

 * Flat file, where the data is saved, its extension is (-flat.vmdk)

grep -i scsi *.vmx

scsi0.virtualDev = "lsilogic"

ls -l v3web-flat.vmdk

-rw-------    1 root     root        12884901888 Jun 19 01:47 v3web-flat.vmdk

vmkfstools -c 12884901888 -a lsilogic -d thin temp.vmdk

rm -i temp-flat.vmdk

mv  -i temp.vmdk v3web.vmdk

# 修改 Router.vmdk

RW 25165824 VMFS "vmdisk0-flat.vmdk"
ddb.thinProvisioned = "1"

 

---

Rename vmdk file

 

Rename a virtual disk

1. Verify the virtual machine referring to the virtual machine disk is powered off

    and does not have outstanding snapshots. (必須)

2. Remove the virtual disk from the virtual machine's configuration (必須)

3. -E, --renamevirtualdisk

vmkfstools -E OldName.vmdk NewName.vmdk

 

---

Check vmdk Consistent

 

-e|--chainConsistent             # to check the entire snapshot chain

-v --verbose

-x --fix [check|repair]          # check or repair a virtual disk if it gets corrupted

# check vmdk

vmkfstools -x check /vmfs/volumes/my_datastore/my_disk.vmdk

 

---

Troubleshoot

 

行以下 cmd

vmkfstools -i "/vmfs/volumes/datastore1/vm1/disk-flat.vmdk" \
-d thin "/vmfs/volumes/iscsi_bak/vm1/d.vmdk"

Error

DiskLib_Check() failed for source disk The file specified is not a virtual disk (15).

原因

Leave -flat out of the destination and source file name !!