Messages in this thread | | | Date | Fri, 08 Feb 2008 13:37:28 +0300 | From | Vladislav Bolkhovitin <> | Subject | Re: Integration of SCST in the mainstream Linux kernel |
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david@lang.hm wrote: > On Thu, 7 Feb 2008, Vladislav Bolkhovitin wrote: > >> Bart Van Assche wrote: >> >>> - It has been discussed which iSCSI target implementation should be in >>> the mainstream Linux kernel. There is no agreement on this subject >>> yet. The short-term options are as follows: >>> 1) Do not integrate any new iSCSI target implementation in the >>> mainstream Linux kernel. >>> 2) Add one of the existing in-kernel iSCSI target implementations to >>> the kernel, e.g. SCST or PyX/LIO. >>> 3) Create a new in-kernel iSCSI target implementation that combines >>> the advantages of the existing iSCSI kernel target implementations >>> (iETD, STGT, SCST and PyX/LIO). >>> >>> As an iSCSI user, I prefer option (3). The big question is whether the >>> various storage target authors agree with this ? >> >> >> I tend to agree with some important notes: >> >> 1. IET should be excluded from this list, iSCSI-SCST is IET updated >> for SCST framework with a lot of bugfixes and improvements. >> >> 2. I think, everybody will agree that Linux iSCSI target should work >> over some standard SCSI target framework. Hence the choice gets >> narrower: SCST vs STGT. I don't think there's a way for a dedicated >> iSCSI target (i.e. PyX/LIO) in the mainline, because of a lot of code >> duplication. Nicholas could decide to move to either existing >> framework (although, frankly, I don't think there's a possibility for >> in-kernel iSCSI target and user space SCSI target framework) and if he >> decide to go with SCST, I'll be glad to offer my help and support and >> wouldn't care if LIO-SCST eventually replaced iSCSI-SCST. The better >> one should win. > > > why should linux as an iSCSI target be limited to passthrough to a SCSI > device. > > the most common use of this sort of thing that I would see is to load up > a bunch of 1TB SATA drives in a commodity PC, run software RAID, and > then export the resulting volume to other servers via iSCSI. not a > 'real' SCSI device in sight. > > As far as how good a standard iSCSI is, at this point I don't think it > really matters. There are too many devices and manufacturers out there > that implement iSCSI as their storage protocol (from both sides, > offering storage to other systems, and using external storage). > Sometimes the best technology doesn't win, but Linux should be > interoperable with as much as possible and be ready to support the > winners and the loosers in technology options, for as long as anyone > chooses to use the old equipment (after all, we support things like > Arcnet networking, which lost to Ethernet many years ago)
David, your question surprises me a lot. From where have you decided that SCST supports only pass-through backstorage? Does the RAM disk, which Bart has been using for performance tests, look like a SCSI device?
SCST supports all backstorage types you can imagine and Linux kernel supports.
> David Lang > - > To unsubscribe from this list: send the line "unsubscribe linux-scsi" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
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