HARD DISKS FINALLY NOW CHEAPER

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Thanks to the decline and fall of Chia the price of hard disks is now back on track with the price deflator. Chia has been widely reported as being pointless now that the chance of winning a coin is so low. Now the farmers are stuck with hard disks galore with very little resale value. The reason is that the workload ratings has been exceeded extensively. The likely failure rates are much higher than a typical gaming box or a server.

Drive managed shingled disks (DMSD) are the lowest cost per GB in the market. Server disks are using perpendicular media recording (PMR) along with helium to allow more plates to be used. Two-dimensional magnetic recording (TDMR) was proposed in 2008 as a means of pushing beyond 1 Tbit/in2 areal-density yet staying with relatively conventional magnetic components. The industry has struggled to advance the new heat assisted media (HAMR). Seagate has had one model in trials for a year now but it takes time to really see how well the new technology pans out. WD has been offering hybrid SSD hard disk units to boost performance.

Seagate had been shipping HDDs with TDMR since 2017. This was followed by Western Digital in 2018 and Toshiba in 2019. These actual first implementations of TDMR are much simpler and very different to the scenario originally envisioned above. Current implementations recover only a single track using a read head with just two read-elements stacked one above the other (i.e. downtrack) and rely on the skew arising from the use of a rotary actuator to create some cross-track separation between the sensors.

Seagate has been developing a new disk technology. The drives are PMR with TDMR heads and are set to be generally available, unlike the company’s current 20TB HDDs based on heat-assisted magnetic recording technology that are only available to select customers. It is known that Seagate is now manufacturing these new TDMR disks in volume.

I have four of the Seagate ST8000DM004 which are now down to $179.99 shipped in Canada. The launch price was close to $244.99 in Canada. DMSD disks are not suitable for NAS use however for JBOD use they are perfect.

I have one server grade 12TB hard disk which handles the active game collection. DMSD are not able to handle the drive writes that server class hard disks are designed for. Media libraries tend to be static which is a strength of the DSMD disks,

One of the ST8000DM004 hosts my iTunes media library. The disk can hold an astronomical amount of music which means every CD at thrift stores is not a problem. A second ST8000DM004 handles the downloads and the remaining two are used for game storage.

A density of approximately 1 Tbit/in2 is considered to be the limit for conventional perpendicular magnetic recording. The original concept for TDMR has evolved greatly since it was originally proposed.

Seagate’s Exos 2X14 14TB HDD is basically two 7TB drives crammed into a 3.5-inch hermetically sealed helium-filled chassis. The device features a 7200 RPM spindle speed, is equipped with a 256MB multi-segmented cache, and uses a single-port SAS 12Gb/s interface. These disks are more expensive than standard hard disks but they are substantially faster.

Hard disks have increased the RAM cache over time and some models of hard disks now have 512MB which is enough to handle a busy workload. As RAM has become less expensive its likely 1GB will be seen on a hard disk before long.

Long ago when Netware was a thing, elevator seeking was used to handle multiple users. Modern server class hard disks can handle that algorithm but SSD servers have displaced the need for high performance RAID arrays. Today hard disks are largely stuffed into large server boxes which are then mounted on racks. Better servers use advanced controllers to be able to deliver better performance.

SSD prices have also eased in price too. Somebody needs come up with a new controller can can handle more than 8TB so that larger model hardware can be manufactured.

For the time being the storage is not stressed and there is lots of room for more games.