Free space
Eirik
1 Post
May 19, 2017, 10:38 amQuote from Eirik on May 19, 2017, 10:38 amHi 🙂
I love this project 🙂
I have tested PetaSAN on VMwware.
When i delete a file on the ISCSI disk on VMware it doesn't free up space on the PetaSAN cluster.
Any fix for this ?
Hi 🙂
I love this project 🙂
I have tested PetaSAN on VMwware.
When i delete a file on the ISCSI disk on VMware it doesn't free up space on the PetaSAN cluster.
Any fix for this ?
admin
2,918 Posts
May 19, 2017, 4:05 pmQuote from admin on May 19, 2017, 4:05 pmThanks very much for your nice comment.
Actually the free space reported by PetaSAN is the correct behavior. PetaSAN works at the SAN/disk/block/sector level, it reports free space at that level, it does not understand files. It is the iSCSI client side, such as VMWare ESXi/Windows/Hyper-V, that formats the SAN disk to create an NTFS-CSV/VMFS volume which understands the concept of files.
For example if using a PetSAN disk on Windows formatted as NTFS and copy a large file on it, the filesystem will write a lot of block sectors to PetaSAN that may take a long time to complete and PetaSAN will show the raw space available going down. If you delete the file in Windows it will be very quick, since all it does is flag some file system table (at the file system layer) that these block are no longer allocated, but PetaSAN or any other SAN will not be aware of this. Of course if you copy another large file, it will use/overwrite the same sectors of the first file and the free space on the PetaSAN side will not change if the 2 files are have same size
If you need to know what free space you have on an NTFS formatted PetaSAN disk, you need to as ask this on the Windows side. If you need to know if you need to buy physical disks for you cluster, you need to check the free space reported by PetaSAN.
Thanks very much for your nice comment.
Actually the free space reported by PetaSAN is the correct behavior. PetaSAN works at the SAN/disk/block/sector level, it reports free space at that level, it does not understand files. It is the iSCSI client side, such as VMWare ESXi/Windows/Hyper-V, that formats the SAN disk to create an NTFS-CSV/VMFS volume which understands the concept of files.
For example if using a PetSAN disk on Windows formatted as NTFS and copy a large file on it, the filesystem will write a lot of block sectors to PetaSAN that may take a long time to complete and PetaSAN will show the raw space available going down. If you delete the file in Windows it will be very quick, since all it does is flag some file system table (at the file system layer) that these block are no longer allocated, but PetaSAN or any other SAN will not be aware of this. Of course if you copy another large file, it will use/overwrite the same sectors of the first file and the free space on the PetaSAN side will not change if the 2 files are have same size
If you need to know what free space you have on an NTFS formatted PetaSAN disk, you need to as ask this on the Windows side. If you need to know if you need to buy physical disks for you cluster, you need to check the free space reported by PetaSAN.
Last edited on May 19, 2017, 4:07 pm · #2
Free space
Eirik
1 Post
Quote from Eirik on May 19, 2017, 10:38 amHi 🙂
I love this project 🙂
I have tested PetaSAN on VMwware.
When i delete a file on the ISCSI disk on VMware it doesn't free up space on the PetaSAN cluster.
Any fix for this ?
Hi 🙂
I love this project 🙂
I have tested PetaSAN on VMwware.
When i delete a file on the ISCSI disk on VMware it doesn't free up space on the PetaSAN cluster.
Any fix for this ?
admin
2,918 Posts
Quote from admin on May 19, 2017, 4:05 pmThanks very much for your nice comment.
Actually the free space reported by PetaSAN is the correct behavior. PetaSAN works at the SAN/disk/block/sector level, it reports free space at that level, it does not understand files. It is the iSCSI client side, such as VMWare ESXi/Windows/Hyper-V, that formats the SAN disk to create an NTFS-CSV/VMFS volume which understands the concept of files.
For example if using a PetSAN disk on Windows formatted as NTFS and copy a large file on it, the filesystem will write a lot of block sectors to PetaSAN that may take a long time to complete and PetaSAN will show the raw space available going down. If you delete the file in Windows it will be very quick, since all it does is flag some file system table (at the file system layer) that these block are no longer allocated, but PetaSAN or any other SAN will not be aware of this. Of course if you copy another large file, it will use/overwrite the same sectors of the first file and the free space on the PetaSAN side will not change if the 2 files are have same size
If you need to know what free space you have on an NTFS formatted PetaSAN disk, you need to as ask this on the Windows side. If you need to know if you need to buy physical disks for you cluster, you need to check the free space reported by PetaSAN.
Thanks very much for your nice comment.
Actually the free space reported by PetaSAN is the correct behavior. PetaSAN works at the SAN/disk/block/sector level, it reports free space at that level, it does not understand files. It is the iSCSI client side, such as VMWare ESXi/Windows/Hyper-V, that formats the SAN disk to create an NTFS-CSV/VMFS volume which understands the concept of files.
For example if using a PetSAN disk on Windows formatted as NTFS and copy a large file on it, the filesystem will write a lot of block sectors to PetaSAN that may take a long time to complete and PetaSAN will show the raw space available going down. If you delete the file in Windows it will be very quick, since all it does is flag some file system table (at the file system layer) that these block are no longer allocated, but PetaSAN or any other SAN will not be aware of this. Of course if you copy another large file, it will use/overwrite the same sectors of the first file and the free space on the PetaSAN side will not change if the 2 files are have same size
If you need to know what free space you have on an NTFS formatted PetaSAN disk, you need to as ask this on the Windows side. If you need to know if you need to buy physical disks for you cluster, you need to check the free space reported by PetaSAN.