SAS HDD Drive

[Octocontrabass]

type lspci to see on your computer.

That shows drive controllers, but not the drives themselves. I'm asking because tsdnz seems to be saying that there is some "PCI list" that includes the drives.

[Geri]

I'm asking because tsdnz seems to be saying that there is some "PCI list" that includes the drives.

if he tries to say that, then he is wrong

[LtG]

Initially you said, maybe it's just poor wording:

The idea is that instead of using TRIM as soon as a block is no longer in use, it's faster for an OS to wait in the hope that the block can be reused/reallocated; and if the block is reused/reallocated then the TRIM can be skipped (and therefore performance can be improved).

Your explanation doesn't seem to have anything to do with the above. If you don't issue TRIM and you _attempt_ to reuse/reallocate a block then the SSD will internally do effectively a TRIM on that block anyway. Given that you can't actually rewrite anything, it has to be erased first which is what TRIM does.

So how is it faster for an OS to wait in the hopes it can reuse/reallocate, when you can't reuse/reallocate but instead have to erase first and it's this erasure that is slow, which is why TRIM exists.

Also, you should of course prioritize TRIM requests with initially low priority and as soon as non-trimmed increase in numbers you give it higher priority because otherwise it will start impacting performance at some point. In practice for most cases this dynamic prioritization isn't necessary because I would expect most systems not to be so heavily loaded and thus low priority TRIM's should get thru soon enough.

[simeonz]

I believe that the OP is using another OS - Linux, FreeBSD, etc, and probably expects to see the storage devices using lsblk, camcontrol devlist, etc. I don't know why he mentions PCI per se.

Apparently LSI produces two flavors of cards - "dumb" HBA and "smart" RAID. The OP's card is a smart RAID card. The HBAs use something called LSI Logic Fusion Message Passing Technology (MPT) v1 or v2 for interfacing with the driver and can directly export connected SATA/SAS devices to the OS as is. In this case, the devices can be easily migrated to other SAS/SATA controllers. The RAID controllers use another LSI MegaRAID Firmware Interface (MFI) to communicate with the driver and export the SATA/SAS devices as part of virtual drives. Those virtual drives could be configured as single raid0 JBOD-style drive, but the storage is still imprinted with LSI's controller's metadata and cannot be migrated around easily. Also, the above protocols have to be used in all cases, and AHCI cannot be used even for the SATA ports. The FreeBSD and Linux drivers expose the SATA and SAS devices as scsi, whether they are attached to HBA or RAID controller and no matter how they are configured.

I didn't find a single specification or document about those protocols. That being said, coreboot+seabios have boot support for MFI/MPT, QEMU can emulate an MFI controller, Linux and FreeBSD have drivers for those as well. Not many official manuals, yet everyone knows how to do it from somewhere.

Here are some links that OP might want to read:
Confused about that LSI card? Join the crowd ...
Switching LSI SAS 2208 and similar chipsets to JBOD mode
Configuring JBOD with a LSI 2208 controller

[Schol-R-LEA]

Hi All, Almost feels like the topic has gone off course a little.

It happens. Unfortunately, there are a lot of people here who are under the delusion that someday another human being might actually install their OS.

And if you think anyone who isn't another OS dev will ever do that, well, your commitment order should be arriving any day now.

[tsdnz]

Hi, I meant SATA controller(s) on the PCI bus list, where the SATA drives are in the PORT[n].

Ali

[LtG]

Hi, I meant SATA controller(s) on the PCI bus list, where the SATA drives are in the PORT[n].

So you mean you have a PCI SATA controller and it is not showing on the PCI bus? Have you tried some other OS, like Linux, does it show up there on the PCI bus?

Or is the SATA controller listed but you can't find the drives connected to the controller?

[tsdnz]

Hi All, Almost feels like the topic has gone off course a little.

It happens. Unfortunately, there are a lot of people here who are under the delusion that someday another human being might actually install their OS.

And if you think anyone who isn't another OS dev will ever do that, well, your commitment order should be arriving any day now.

For-sure...

Everyone has such enthusiastic energy, it is really great to see.
There is so much knowledge and willingness to share it is exciting for me to watch everyone.
I would love to get everyone in the same room thrashing out ideas, testing, and coding.
It would be really interesting, EGO's aside, I think it would go well.
When I make my first billion I will fly people over. LOL. Promise!

Ali

[tsdnz]

Hi, I meant SATA controller(s) on the PCI bus list, where the SATA drives are in the PORT[n].

So you mean you have a PCI SATA controller and it is not showing on the PCI bus? Have you tried some other OS, like Linux, does it show up there on the PCI bus?

Or is the SATA controller listed but you can't find the drives connected to the controller?

Hi, I was not very careful when typing in my problem. Basically frustrated that I had to learn and code the different RAID Controller protocols, as I have heaps of servers with RAID controllers in them and no SAS or SATA controllers.
I was hoping that the RAID Controller I had could be selected by something as simple as a checkbox, that when selected it would act as either a SATA or SAS controller depending on the drives installed. On another test server I have a RAID controller and it displayed it's self as an IDE controller, I was too lazy to open it up and check for a IDE controller and assumed the RAID controller has an option to do this. I still have not opened it up to see, I will get my daughter off to school and have a look then. Basically I want to write the storage code, just great fun...

I do apologise to all for the quickly written "my issue, boo hoooo, grrrrrrr, darn no protocol, no docs...." message, and I thank everyone for their time and responses.

And I am impressed with everyone's passion and knowledge, you all have something to offer, it is a pity I live so far away. Oh well, the first billion is one its way.

I have a SATA controller on the way, this should resolve my issues.

Kindly thanking everyone again. Ali