Given what we see at customers I am leaning towards the SCSI level <=2 to ensure the older LTO5's are supported. The newer ones should be backwards compatible. I may have an older LTO5 showing up that wont need a F/W update to work, and will be able to add a "tested by" once I get it.
But lets see what the others have to say Laurence Oberman Principal Software Maintenance Engineer Red Hat Global Support Services ----- Original Message ----- From: "Kai Mäkisara (Kolumbus)" <kai.makis...@kolumbus.fi> To: "Shane M Seymour" <shane.seym...@hpe.com> Cc: "Laurence Oberman" <lober...@redhat.com>, "Emmanuel Florac" <eflo...@intellique.com>, "Laurence Oberman" <oberma...@gmail.com>, linux-scsi@vger.kernel.org Sent: Thursday, January 21, 2016 3:58:46 PM Subject: What partition should the MTMKPART argument specify? Was: Re: st driver doesn't seem to grok LTO partitioning > On 15.1.2016, at 2.21, Seymour, Shane M <shane.seym...@hpe.com> wrote: > > Unfortunately I'm unable to lay my hands on an LTO 5 tape drive so I'm not > able to test that it works either. If it helps at all I can test in the > negative and make sure that for an LTO 3 drive it fails gracefully but that's > about it at the moment. Thanks for all testers and those who attempted to test. The latest patch applies the standard quite strictly and I think it should work with most drives. The implementation can be fixed later if problems are found. However, before making the final patch, we should decide which partition the specified size should apply to. For the SCSI level <=2 it applies to partition 1. For other drives we may have some freedom to “tune” the definition. The size should apply to the partition the users expect it to apply. The current documentation says "the argument gives in megabytes the size of partition 1 that is physically the first partition of the tape”. The documentation I have found for current drives (HP and IBM LTO, IBM 3592, Storagetek T1000) all number the partitions sequentially from the start of the tape. The access time for any partition is probably about the same when wrapwise partitioning is used. It does matter with linear partitioning. Unfortunately, the standards leave the numbering to the implementor. Partitioning with two partitions is used for storing index in a small partition and use the rest of the tape for data. In this case, it is probably natural to specify the size of the index. The LTFS definition supports index in any partition. The open source code I have seen seem to default to index in partition 0. The HP and IBM LTO default partitioning (FDP=1) specifies two wraps (minimum) to partition 1 and the rest to 0. There seem to be lot of arguments supporting both possible choices. Should we use the existing definition (1) or change it for the drives supporting SCSI level >= 3 (or supporting FORMAT MEDIUM)? The definition can’t be changed later. This is why we should make a good decision. Opinions? Thanks, Kai -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
