Is there a way to connect a SAS to an iMac 2011?
And this is the answer, after careful research:

There is NO possible way to do this. SAS cannot be installed on an iMac. Apple likes to surprise its users by making an aluminum shell that cannot be altered. There are SCSI to USB converters, all discontinued, expensive and unreliable. There is the ATTO ThunderLink, which uses the Thunderbolt port, but this costs over a thousand. Likewise, SCSI cannot be installed on an iMac.

The simple solution is that serious computer users who like to perform surgery should purchase a Mac Pro, which can accept SCSI/SAS installations. These computers will work with storage tape. As for iMac, external hard drives (though I would prefer something that won't crash on me after a year of operation) are the only method of huge data storage. $60-$100 will get you a few TB.

Any suggestions on a reliable brand?