Please see this KB article for the full details: https://www.dell.com/support/kbdoc/en-uk/000185734/end-of-life-documents?lang=en

I get an error that this article is "permission based find another article". 

Hello platinumpoint,

Here is what the article states:

what is the end of sale date for Dell Unity XT 480???

Hi,

Thanks for your question.

We have stopped releasing exact end of sale and service dates, but it seems like it has happened already for it. Does it still show under warranty?

Let us know if you have any additional questions.

@DELL-Josh Cr​ I am planning to buy Dell Unity XT 480 with 75 TiB with SSD and 200 TB with NL-SAS drives. hence need to know when this storage will be end of sale and accordingly end of suppport.

If you bought one it would go until that warranty expires at the minimum. 

Hello alireza.kayvan,

In order to boot you’re AX4-5F you need to have the first 5 drives in the correct order. You are correct in the order for each SP. The drive that is located in slot4 is the swap space/ hotspare drive for the AX image. If you lose any single drive 0-3, then the drive in slot4 can rebuild the failed drive. So you will need to find that drive in order to get the AX to boot fully.

I am planning to buy a new one if the end of sale is already declared then please suggest any roll over or better storage.

Powerstore is probably the best option. https://www.dell.com/en-us/shop/powerstore/sf/power-store?hve=explore+power-store