RESERVE RELEASE commands emulation.

Software-based VM-centric and flash-friendly VM storage + free version

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nix239

Fri Jun 25, 2004 3:44 pm

My dream for two years has been building Microsoft cluster without any SCSI disk. The key question is that "physical disk" resource type must support RESERVE and RELEASE SCSI commands. Most iSCSI target implementations just translate these commands to undrlying devices. This is a huge limitation however since the device sharing in this scenario is done among multiple iSCSI initiators and the locking mechanism would be better implemented by iSCSI target module itself.

If you succeed it would qualify your software as a breakthrough in SAN technology.

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Nikolay
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anton (staff)
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Tue Feb 27, 2024 9:30 am

Q: What file system do you want on top of your shared block storage?

See, it can't be NTFS, XFS or whatever local file system you think about. You absolutely need something "special" with the distributed lock mechanism. It could be a full-blown clustered file system like Oracle's Clustered File System, VMware's VMFS or maybe IBM's GPFS. It could be a mix of a network and local file system, think about Microsoft's CSVFS (Block access on the cluster owner node + SMB3 path on the other "redirected" nodes in the cluster). Local file systems + lock managers is also possible, but they are rare these days due to the extra cost and comparably low performance. On Windows. Linux is another story, think about SANLock + Clustered LVM on RHV/oVirt and similar virtualization platforms.

https://en.wikipedia.org/wiki/Clustered_file_system

https://learn.microsoft.com/en-us/windo ... uster-csvs

https://www.ovirt.org/develop/developer ... nlock.html

Hope this helped!
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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anton (staff)
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Tue Feb 27, 2024 9:30 am

== thread closed ==
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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