On 2017-09-22 03:15, Carlos E. R. wrote:
On 2017-09-21 20:32, Greg Freemyer wrote:
There is one on plain PCI, but very expensive:
https://www.pccomponentes.com/kingston-hyperx-predator-m2-ssd-480gb-adaptado...
Kingston HyperX Predator M.2 SSD 480GB + Adaptador PCIe 344,59€
It is a combo with a PCI to PCI-e interface, then an SSD in M.2 form factor.
Another solution, but expensive.
It's primarily expensive because of "480GB". If you want that much capacity it will cost you well above $100. If you're only doing this to address swap space, you should be able to get it done with a 128GB SSD. Around $100 for the SSD / adapter card pair.
Well, if I go for one, it will hold swap and system, not data. It will improve things more. But I don't need that much space for that.
Another possibility is dcache or similar.
I will then go for a plain SSD SATA disk. 100..200 GB range. I will then have to consider what port I have free or that I can make free.
Thinking... I could perhaps find a small nvme combo only for swap. I could get one SilverStone ECM21 Adaptador M.2 to PCIe x4 interface 16,95€ (I also found the reverse conversion), then one small NVME disk just for swap. Possibilities: Intel SSD M.2 Optane 16GB 52,54€ Intel SSD M.2 Optane 32GB 86,54€ Intel SSD M.2 Optane 32GB 80,54€, reconditioned. This means that the Intel ones fail often enough. The other two suitable items are: WD Green SSD M.2 120GB 59,95€ Kingston M.2 SATA SSD 120GB 66,95€ Too big to use only for swap, as the system would not be able to boot for them. However, I could use it as "bcache". https://en.wikipedia.org/wiki/Bcache However, in this post: https://lists.opensuse.org/opensuse-factory/2016-07/msg00062.html Johannes Thumshirn <...@suse.de> says: Please be aware that bcache is not actively maintained by it's original author any more and thus marked as or 'Orphan' in the linux kernel's MAINTAINERS file. It also does not have the stability one might expect from it and as it's orphaned it's kind of hard to get fixes back into the kernel. Martin Wilck <...@suse.com> commented: dmcache should be usable on tumbleweed. https://info.varnish-software.com/blog/accelerating-your-hdd-dm-cache-o r-bcache ---- More info: https://en.wikipedia.org/wiki/Dm-cache Jdd tried bcache, apparently he wasn't very happy, I think he reverted, saw a post about it. Performance Comparison among EnhanceIO, bcache and dm-cache. http://lkml.iu.edu/hypermail/linux/kernel/1306.1/01246.html Reading that list, dm-cache doesn't seem easy to setup, on top. Wikipedia says one needs: In dm-cache, creating a mapped virtual block device that acts as a hybrid volume requires three physical storage devices:[6] Origin device – provides slow primary storage (usually an HDD) Cache device – provides a fast cache (usually an SSD) Metadata device – records the placement of blocks and their dirty flags, as well as other internal data required by a cache policy, including per-block hit counts; a metadata device cannot be shared between multiple cache devices, and it is recommended to be mirrored No one has commented recently on the mail lists (searched locally) about using dm-cache, and it is possible that Leap doesn't support it (I have to read to find out). sigh. So I would then need a standard SATA SSD disk to hold just the system, in addition to a small nvme M.2 for swap, as the best (and more expensive) solution. Or, a single SATA SSD for swap and system and swap, which is not that bad a solution. Or, have grub in rotating disk, system on nvme? I doubt it would work. Hum. Wikipedia has more to read: See also bcache – a Linux kernel's block layer cache, developed by Kent Overstreet Flashcache – a disk cache component for the Linux kernel, initially developed by Facebook Hybrid drive – a storage device that combines flash-based and spinning magnetic media storage technologies ReadyBoost – a disk caching software component of Windows Vista and later Microsoft operating systems Smart Response Technology (SRT) – a proprietary disk storage caching mechanism, developed by Intel for its chipsets I didn't know about Flashcache. Let's look at it. https://en.wikipedia.org/wiki/Flashcache «Since January 2013, there is a fork of Flashcache, named EnhanceIO and developed by sTec, Inc.» Not much to read there about actual implementation. https://en.wikipedia.org/wiki/EnhanceIO «Overview» «EnhanceIO makes it possible to add a SSD or other fast disk device as a cache to another block device, such as a hard drive, in order to improve the performance of the disk. It was initially based on Facebook's similar Flashcache module.[1] Unlike Flashcache and other caching solutions, it doesn't use the Linux device mapper[1]. This means it does not create a new block device and caching can be added to existing disks, without reformatting or even unmounting them. This makes it easy to add cache to existing systems.» I like that. Project abandoned, several forks. No hits on our mail archive. Dead end... Sigh. More comments: <https://www.reddit.com/r/DataHoarder/comments/50h9zs/linux_ssd_cacheing_of_spinning_drives_enhanceio/> See the comments on that page... :-( No "*cache" technology for me, then. Stay traditional ;-) -- Cheers / Saludos, Carlos E. R. (from 42.2 x86_64 "Malachite" at Telcontar)