Changeset 105335 in vbox for trunk/doc/manual/en_US/dita/topics/vdidetails.dita
- Timestamp:
- Jul 16, 2024 8:01:22 AM (5 months ago)
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trunk/doc/manual/en_US/dita/topics/vdidetails.dita
r99797 r105335 6 6 7 7 <body> 8 <p> 9 Disk image files reside on the host system and are seen by the 10 guest systems as hard disks of a certain geometry. When a guest OS 11 reads from or writes to a hard disk, <ph conkeyref="vbox-conkeyref-phrases/product-name"/> redirects the 12 request to the image file. 13 </p> 14 <p> 15 Like a physical disk, a virtual disk has a size, or capacity, 16 which must be specified when the image file is created. As opposed 17 to a physical disk however, <ph conkeyref="vbox-conkeyref-phrases/product-name"/> enables you to expand 18 an image file after creation, even if it has data already. See 19 <xref href="vboxmanage-modifymedium.dita"/>. 20 </p> 8 <p>Disk image files reside on the host system and are seen by the guest systems as hard disks of a 9 certain geometry. When a guest OS reads from or writes to a hard disk, <ph 10 conkeyref="vbox-conkeyref-phrases/product-name"/> redirects the request to the image file. </p> 11 <p>Like a physical disk, a virtual disk has a size, or capacity, which must be specified when the image 12 file is created. As opposed to a physical disk however, <ph conkeyref="vbox-conkeyref-phrases/product-name"/> 13 enables you to expand an image file after creation, even if it has data already. See <xref 14 href="vboxmanage-modifymedium.dita"/>. </p> 21 15 <p> 22 16 <ph conkeyref="vbox-conkeyref-phrases/product-name"/> supports the following types of disk image files: … … 24 18 <ul> 25 19 <li> 26 <p> 27 <b outputclass="bold">VDI.</b> Normally, <ph conkeyref="vbox-conkeyref-phrases/product-name"/> 28 uses its own container format for guest hard disks. This is 29 called a Virtual Disk Image (VDI) file. This format is used 30 when you create a new virtual machine with a new disk. 31 </p> 20 <p><b outputclass="bold">VDI.</b> Normally, <ph conkeyref="vbox-conkeyref-phrases/product-name"/> 21 uses its own container format for guest hard disks. This is called a Virtual Disk Image (VDI) file. This 22 format is used when you create a new virtual machine with a new disk. </p> 32 23 </li> 33 24 <li> 34 <p> 35 <b outputclass="bold">VMDK.</b> <ph conkeyref="vbox-conkeyref-phrases/product-name"/> also 36 fully supports the popular and open VMDK container format that 37 is used by many other virtualization products, such as VMware. 38 </p> 25 <p><b outputclass="bold">VMDK.</b> 26 <ph conkeyref="vbox-conkeyref-phrases/product-name"/> also fully supports the popular and open VMDK container 27 format that is used by many other virtualization products, such as VMware. </p> 39 28 </li> 40 29 <li> 41 <p> 42 <b outputclass="bold">VHD.</b> <ph conkeyref="vbox-conkeyref-phrases/product-name"/> also 43 fully supports the VHD format used by Microsoft. 44 </p> 30 <p><b outputclass="bold">VHD.</b> 31 <ph conkeyref="vbox-conkeyref-phrases/product-name"/> also fully supports the VHD format used by Microsoft. </p> 45 32 </li> 46 33 <li> 47 <p> 48 <b outputclass="bold">HDD.</b> Image files of Parallels 49 version 2 (HDD format) are also supported. 50 </p> 51 <p> 52 Due to lack of documentation of the format, newer versions 53 such as 3 and 4 are not supported. You can however convert 54 such image files to version 2 format using tools provided by 55 Parallels. 56 </p> 34 <p><b outputclass="bold">HDD.</b> Image files of Parallels version 2 (HDD format) are also 35 supported. </p> 36 <p>Due to lack of documentation of the format, newer versions such as 3 and 4 are not supported. 37 You can however convert such image files to version 2 format using tools provided by Parallels. </p> 57 38 </li> 58 39 </ul> 59 <p> 60 Irrespective of the disk capacity and format, as mentioned in 61 <xref href="create-vm-wizard.dita#create-vm-wizard"/>, there are two options for 62 creating a disk image: fixed-size or dynamically allocated. 63 </p> 40 <p>Irrespective of the disk capacity and format, as mentioned in <xref 41 href="create-vm-wizard.dita#create-vm-wizard"/>, there are two options for creating a disk image: fixed-size or 42 dynamically allocated. </p> 64 43 <ul> 65 44 <li> 66 <p> 67 <b outputclass="bold">Fixed-size.</b> If you create a 68 fixed-size image, an image file will be created on your host 69 system which has roughly the same size as the virtual disk's 70 capacity. So, for a 10 GB disk, you will have a 10 GB file. 71 Note that the creation of a fixed-size image can take a long 72 time depending on the size of the image and the write 73 performance of your hard disk. 74 </p> 45 <p><b outputclass="bold">Fixed-size.</b> If you create a fixed-size image, an image file will be 46 created on your host system which has roughly the same size as the virtual disk's capacity. So, for a 10 GB 47 disk, you will have a 10 GB file. Note that the creation of a fixed-size image can take a long time depending 48 on the size of the image and the write performance of your hard disk. </p> 75 49 </li> 76 50 <li> 77 <p> 78 <b outputclass="bold">Dynamically allocated.</b> For 79 more flexible storage management, use a dynamically allocated 80 image. This will initially be very small and not occupy any 81 space for unused virtual disk sectors, but will grow every 82 time a disk sector is written to for the first time, until the 83 drive reaches the maximum capacity chosen when the drive was 84 created. While this format takes less space initially, the 85 fact that <ph conkeyref="vbox-conkeyref-phrases/product-name"/> needs to expand the image file 86 consumes additional computing resources, so until the disk 87 file size has stabilized, write operations may be slower than 88 with fixed size disks. However, after a time the rate of 89 growth will slow and the average penalty for write operations 90 will be negligible. 91 </p> 51 <p><b outputclass="bold">Dynamically allocated.</b> For more flexible storage management, use a 52 dynamically allocated image. This will initially be very small and not occupy any space for unused virtual 53 disk sectors, but will grow every time a disk sector is written to for the first time, until the drive reaches 54 the maximum capacity chosen when the drive was created. While this format takes less space initially, the fact 55 that <ph conkeyref="vbox-conkeyref-phrases/product-name"/> needs to expand the image file consumes additional 56 computing resources, so until the disk file size has stabilized, write operations may be slower than with 57 fixed size disks. However, after a time the rate of growth will slow and the average penalty for write 58 operations will be negligible. </p> 92 59 </li> 93 60 </ul>
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