Hello, It is also the OS/filesystem that must support the TRIM or UNMAP command. I.e. in EXT4 you have to set the option 'discard' when mounting a volume to support TRIM/UNMAP feature. Using something like 'fsttrim'
If your backend storage is RAIDed then typically any SSDs are not presented as SSD/FLASH drives to the host. Physical drives are virtualized by the RAID controller and LUNs are presented to the host. Once the TRIM/UNMAP command is sent it's up to the backend storage device to handle that properly. Open-iSCSI itself is the transport to the target from the OS. It does not initiate TRIP/UNMAP or any other SCSI commands on its own. It will pass along those SCSI commands the OS sends and send back all results. Regards, Don On Wed, May 26, 2021 at 10:33 AM 'H. Giebels' via open-iscsi < [email protected]> wrote: > I think I've got it. It is the emulate_tpu parameter on the target side. > Needs some more confirmation, though > > H. Giebels schrieb am Mittwoch, 26. Mai 2021 um 15:26:39 UTC+2: > >> >> Hello, >> >> not exactly sure, wether this is an issue of targetcli or open iscsi. The >> target lun is a sparse file, and I would like to be able to trim that lun >> to reclaim free space. Think thin volume on a file backend. >> >> Now iscsiadm -m session shows me (non-flash), what I suppose is the >> reason, why I get an operation not permitted error when trying to so so. >> >> The manpage talks about a flash node, but it is nowhere explained, what >> that is and wether this is related to flash storage at all. So maybe there >> is some documentation about the terms used? >> >> But primarily I would like to know, wether the information about the >> trimability is a matter of the target advertising it or wether this has to >> be defined during creation of the lun on the client side (-o new). >> >> Thanks >> >> Hermann >> >> >> -- > You received this message because you are subscribed to the Google Groups > "open-iscsi" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/open-iscsi/086c0e6e-4df9-409c-80a4-d611fd36a363n%40googlegroups.com > <https://groups.google.com/d/msgid/open-iscsi/086c0e6e-4df9-409c-80a4-d611fd36a363n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/open-iscsi/CAK3e-EYB3NurR6MzAzf2WBRUMDiKKbH23w3OFF8u86zW-nRj-g%40mail.gmail.com.
