Quoting Julien Goodwin (luv-lists@studio442.com.au):

SSHD = classic HDD with some SSD caching

As the maintainer of http://linuxmafia.com/ssh/ I looked forward to a long thread mutt told me had Subject header SSHD, hoping to hear about some SSH daemons I'd not previously discovered.

On Tue, Jan 12, 2016 at 05:18:23PM +1100, Tennessee Leeuwenburg wrote:

Based on my general new article reading, I thought everything above 6GB was using shingled storage which doesn't interest me so much. I'd be interested if you find out otherwise.

dunno about all drives 6TB and above, but definitely the Seagate Archive drives (MSY have 6 & 8TB models, and IIRC Seagate recently-ish released a 10TB model). I've got a set of 4 x 4TB Seagate SSHDs, have no complaints about either quality or performance. I've only got them because I had one (which i was intending to use in my win7 steam games box) when I urgently needed to upgrade my ZFS 'backup' pool, so i bought another 3 and set them up as 2 mirrored pairs (for a total of 8TB). I'm not using any ZIL or SSD L2ARC on the backup pool so having the 4GB SSD cache (per drive) on it is probably beneficial. I haven't done any performance testing (the urgency of the upgrade - the backup pool had hit 90+% utilisation which is around where ZFS peformance goes to absolute shit - precluded running bonnie++ before use) but they seem reasonably fast to me, for magnetic spinning disks. they're certainly no worse than non-SSHD disks and cost about the same - a little cheaper than a Seagate NAS or WD Red. $ zpool list -v backup NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT backup 7.25T 2.54T 4.71T - 20% 35% 1.00x ONLINE - mirror 3.62T 1.27T 2.35T - 20% 35% sdb - - - - - - sdi - - - - - - mirror 3.62T 1.27T 2.35T - 20% 35% sdd - - - - - - sdc - - - - - - $ list_disks | grep sd[bicd] sdb ST4000DX001-1CE168_Z303PTHA sdc ST4000DX001-1CE168_Z302ZSGB sdd ST4000DX001-1CE168_Z303PVZ9 sdi ST4000DX001-1CE168_Z303PSH6 craig ps: if anyone's wondering what 'list_disks' is, it's an alias of mine: (line breaks and indentation added for readability) alias list_disks='find /dev/disk/by-id/ -type l | awk '\''/\/(s?ata|usb|scsi)/ && ! /-part[0-9]/'\'' | while read disk ; do echo $(basename $(readlink $disk)) $(basename $disk); done | sort' can be saved as a script instead of an alias, just change the '\'' (which is how you quote single-quotes inside other single-quotes) to plain ' i should probably simplify that one day and do the basename and readlink stuff in awk rather than in a while read loop. may as well do it now: alias list_disks2='find /dev/disk/by-id/ -type l | awk '\''@load "filefuncs" ; /\/(s?ata|usb|scsi)/ && ! /-part[0-9]/ { stat($1,sd) ; gsub(/^.*\//,"",sd["linkval"]) ; gsub(/^.*\//,"",sd["name"]) ; print sd["linkval"], sd["name"] }'\'' | sort' this will only work with GNU awk, won't work in other awks because it needs the filefuncs extension for stat(), and only gawk has extensions. the downside is that it's not actually any simpler. certainly no easier to read and understand. it is much more efficient because it avoids executing external programs 'basename' and 'readlink' repeatedly, but that's not really an issue on modern systems. my preference is to optimise for readability (so i know WTF i was thinking in 6 months time) rather than performance for shell/awk/etc scripts. -- craig sanders <cas@taz.net.au> BOFH excuse #247: Due to Federal Budget problems we have been forced to cut back on the number of users able to access the system at one time. (namely none allowed....)

On 13 January 2016 at 13:28, Trent W. Buck via luv-main <luv-main@luv.asn.au

wrote:

Russell Coker via luv-main <luv-main@luv.asn.au> writes:

...

http://cdn.msy.com.au/Parts/PARTS.pdf https://en.wikipedia.org/wiki/Hybrid_drive https://en.wikipedia.org/wiki/Shingled_magnetic_recording

Are SSHDs any good?

AFAICT the only reason SSHDs exist are:

* Windows has nothing like bcache/l2arc; or * My computer only has one disk bay.

That is, if you have a commodity server, you're much better off buying the HDD and SSD components separately.

(Am I wrong?)

Slightly off topic, I did put one into my PS3 to upgrade the native 128Gb disk to 500Gb. The cache components showed marginal improvement in game load times but only on games that were most played. -- Colin Fee tfeccles@gmail.com