ST900MM0099 - NAND or not NAND?

[Springdale]

Hello All,

So I have bought some of these drives on eBay for a fairly good price. Seagate's model numbering is quite confusing, also this drive is not listed on their website since it seems to be a NetApp OEM drive. The same drive but with 600GB size, ST600MM0099 is listed as a 4Kn (switchable to 512E via Seagate fastformat), 256MB cache drive with 16GB eMLC NAND for "Enhanced caching features".

I could not find any proof that the ST900MM0099 has NAND cache, but I wanted to find out. The drive is quite fast:

I had the idea of asking Seagate Support. First, they did not understand what I meant. They asked me to explain what eMLC is After a few round they have confirmed that while the drive has 256MB cache it does not use eMLC NAND cache. Bummer. Somehow I did not believe them and had the idea to carefully remove the PCB. Surprise:

Looking up the part numbers, to the right is a 256MB Samsung DDR3, to the left is... 16GB Hynix MLC NAND.

Now I kindly asked Seagate support to confirm if the drive has NAND cache installed but disabled (not likely).

What do you think?

[fzabkar]

This is all I could find (I see you have found the same).

Enterprise Performance 10K HDD v9 SAS Product Manual (includes ST1200MM0009 and ST600MM0009, which are standard 512N models):
https://www.seagate.com/files/www-content/product-content/enterprise-performance-savvio-fam/ent-perf-10k-hdd-v9-skybolt/en-us/docs/100818015f.pdf

The Advanced Caching functionality (available on 512E/4Kn only) provides improved performance over standard HDDs in real-world workloads. This improvement is due to the addition of a solid state component that caches “hot” data for reads as well as protects write data via non-volatile cache (NVC).

8MB NVC-backed write cache 512E/4Kn only

Enterprise Performance 10K HDD v9 Data Sheet:
https://www.seagate.com/www-content/datasheets/pdfs/enterprise-performance-10k-hddDS1929-1C-1704US-en_US.pdf

NAND Flash Type eMLC
NAND Flash Size 16GB

Internal Name: Skybolt

https://www.seagate.com/files/www-content/support-content/compliance/_shared/masters/Exos%2010E2400%20Regulatory%20Certification%20Document.pdf

[Springdale]

fzabkar, thank you for your reply

If you check this you can see there is an ST600MM0099 that has the NAND cache. I would think my drive is the same except the size, but with the Seagate model numbering, who knows...

https://www.seagate.com/www-content/dat ... -en_US.pdf

Also the drive is 4Kn/512E, that's for sure. It even has the AF logo on its label.

Seagate support replied that they have escalated the issue. Fingers crossed

[Springdale]

So I have got the below reply:

As a follow up email, I would like to inform you that the drive ST900MM0099 is hybrid meaning that it has a small SSD or NAND part that works along with the rest of the component for a faster performance. This SSD part is not directly accesible for the end-user but rather a specific component of the drive itself that allows a better performance for the drive.

I hope I managed to answer your queries above but if not please let me know and I will assist you further.

Looking for immediate assistance? You can have real-time support through our phone or web messaging services which are available during Seagate’s customer support business hours.

You will find Seagate’s support hours and how to contact us here:
https://www.seagate.com/contacts/

Thank you for contacting Seagate!
Kind Regards,

Seems like Seagate support = monkeys. But at least the case is closed