So, I think I need to ask you all for some help because being an old-timer from the 2010's and now looking to enhance my storage and disk systems... I am bedazzled by the enormous amount of various options currently available... in such a variety it makes SCSI standards look like a walk in the park!
What I'll do is make a list here of what I think is going on, and I welcome all your corrections and explanations where mistakes are being made
ASSUMED STATE OF AFFAIRS:
1. SFF-8643 is for 12G SAS cards.
2.MiniSAS is a common name for an SFF-8643 connector
3. SFF-8643 is also used to connect a single NVME or U.2 drive
4. However, some adapters offering SFF-8643 connectors may only support U.2/NVME drives (and NOT SAS/SATA)
5. A single SFF-8643 connector can be connected to only ONE U.2 Drive
6. However, a single SFF-8643 connector can also support 4x "conventional" SAS or SATA drive
7. Speed aside, a SFF-8643 and SFF-8087 are identical when it comes to their SAS/SATA features/properties
8. An OcuLink (SFF-8611) is the same as SFF-8643, just smaller
9. An OcuLink (therefore) can also support 4x SAS/SATA drive (though the host adapter may not?)
10. SFF-8654 is an 8-lane connector, which can be "converted" into 2x SFF-8087 or 2x SFF-8643
11. SFF-8654 is a sneaky little bastard because it actually exists in two versions (4i and 8i) which are both called SFF-8654 (or SlimSAS!) but are NOT the same size
12.For ultimate confusion there also exits a SFF-8654 LP Low Profile connector
13. Finally, there is also an MCIO connector (SFF-TA-1016 8i) which is different from SFF-8654 in appearance but is electrically identical to SFF-8654 8i
Questions:
A. Can a SFF-8087 connector (at least in theory, assuming a card would support it) also be used to connect a U.2 disk?
B. What happens when you attach a U.2 disk to a SAS backplane? Does this even fit?
C. Will an NVME host adapter like the LSI9300-16i support/see/recognize a SAS or SATA disk?
D. Does U.2 always imply the disk is ALSO NVME? Are there U.2 disks without NVME?
E.Is the LSI9300-16i card (and similar NVME-focused adapters) also a RAID card?
F. Why does it seem like the entire concept of RAID is mostly alien/not applicable to U.2 and NVME drives?
G. Why are there so few M.2 adapters which support "old-school" RAID (e.g. RAID 5)
H. Why are there so few M.2 SSD bearing adapters which do not require bifurcation?
I. Can one mix U.2/NVME drives (connected using SFF-8643 to SFF-8639) with SAS/SATA disks (using SFF-8643 to 4x SATA, say) on the same adapter, and would this decrease the performance of some drives?
J. Why does it appear to be the case that M.2 drives/slots can be rather fickle and picky with the drives they support?
K. What is the max speed of a U.2 drive (interconnect)?
L. Why are U.2 disks not keeping pace with M2. disk speeds?
M. How important are cable lengths when it comes to high-speed (2GB/s or more) disk drives (of any of the types mentioned here)
N. How stable/reliable are those funny M.2 cards with 4x (or more!) SATA ports on them? Does this generally work well?
O. Assuming the Motherboard supports SATA RAID mode on the onboard ports, can disks attached to a SATA-via-M.2 adapter be added to a RAID array (with any number of drives connected to the onboard SATA ports)
P. To what end do we have THAT MANY various connector types, standards, speeds and other varieties of what are far fewer ACTUAL differences?
Q. What might be the reasons for there not being an easy to use click and release system for M.2 disks like we've had for "regular" drives since the nineties (for SCSI,SATA and SAS)?
R. And last but not least... The LSI 3Ware 9650SE 24-port SATA Raid card has a 3x 8-lane connector which does not seem to have an SFF "code"/model. Even Broadcom calls it a "multi-lane connector" without bothering to provide more details. I am gonna go ahead and assume that this is NOT identical to an SFF-8654 8i connector, as this would make things simpler, correct?
What I'll do is make a list here of what I think is going on, and I welcome all your corrections and explanations where mistakes are being made
ASSUMED STATE OF AFFAIRS:
1. SFF-8643 is for 12G SAS cards.
2.MiniSAS is a common name for an SFF-8643 connector
3. SFF-8643 is also used to connect a single NVME or U.2 drive
4. However, some adapters offering SFF-8643 connectors may only support U.2/NVME drives (and NOT SAS/SATA)
5. A single SFF-8643 connector can be connected to only ONE U.2 Drive
6. However, a single SFF-8643 connector can also support 4x "conventional" SAS or SATA drive
7. Speed aside, a SFF-8643 and SFF-8087 are identical when it comes to their SAS/SATA features/properties
8. An OcuLink (SFF-8611) is the same as SFF-8643, just smaller
9. An OcuLink (therefore) can also support 4x SAS/SATA drive (though the host adapter may not?)
10. SFF-8654 is an 8-lane connector, which can be "converted" into 2x SFF-8087 or 2x SFF-8643
11. SFF-8654 is a sneaky little bastard because it actually exists in two versions (4i and 8i) which are both called SFF-8654 (or SlimSAS!) but are NOT the same size
12.For ultimate confusion there also exits a SFF-8654 LP Low Profile connector
13. Finally, there is also an MCIO connector (SFF-TA-1016 8i) which is different from SFF-8654 in appearance but is electrically identical to SFF-8654 8i
Questions:
A. Can a SFF-8087 connector (at least in theory, assuming a card would support it) also be used to connect a U.2 disk?
B. What happens when you attach a U.2 disk to a SAS backplane? Does this even fit?
C. Will an NVME host adapter like the LSI9300-16i support/see/recognize a SAS or SATA disk?
D. Does U.2 always imply the disk is ALSO NVME? Are there U.2 disks without NVME?
E.Is the LSI9300-16i card (and similar NVME-focused adapters) also a RAID card?
F. Why does it seem like the entire concept of RAID is mostly alien/not applicable to U.2 and NVME drives?
G. Why are there so few M.2 adapters which support "old-school" RAID (e.g. RAID 5)
H. Why are there so few M.2 SSD bearing adapters which do not require bifurcation?
I. Can one mix U.2/NVME drives (connected using SFF-8643 to SFF-8639) with SAS/SATA disks (using SFF-8643 to 4x SATA, say) on the same adapter, and would this decrease the performance of some drives?
J. Why does it appear to be the case that M.2 drives/slots can be rather fickle and picky with the drives they support?
K. What is the max speed of a U.2 drive (interconnect)?
L. Why are U.2 disks not keeping pace with M2. disk speeds?
M. How important are cable lengths when it comes to high-speed (2GB/s or more) disk drives (of any of the types mentioned here)
N. How stable/reliable are those funny M.2 cards with 4x (or more!) SATA ports on them? Does this generally work well?
O. Assuming the Motherboard supports SATA RAID mode on the onboard ports, can disks attached to a SATA-via-M.2 adapter be added to a RAID array (with any number of drives connected to the onboard SATA ports)
P. To what end do we have THAT MANY various connector types, standards, speeds and other varieties of what are far fewer ACTUAL differences?
Q. What might be the reasons for there not being an easy to use click and release system for M.2 disks like we've had for "regular" drives since the nineties (for SCSI,SATA and SAS)?
R. And last but not least... The LSI 3Ware 9650SE 24-port SATA Raid card has a 3x 8-lane connector which does not seem to have an SFF "code"/model. Even Broadcom calls it a "multi-lane connector" without bothering to provide more details. I am gonna go ahead and assume that this is NOT identical to an SFF-8654 8i connector, as this would make things simpler, correct?