18 ms·
Linode SSD Beta
- fletchowns 13y agoThis sounds pretty cool! What sorts of considerations does one make when you are deciding between more RAM or SSDs? Random IO is processed first through the SSDs (the thing that they are really good at) while sequential IO short-cuts to the hard drives - which is pretty slick. I'm curious, what do you use to develop something like that? Is it build on top of something? Built into the kernel? I wouldn't even know where to begin...
- bingaling 13y agoSounds like SSD's are used as a cache, like ZFS does with its l2arc.
- jevinskie 13y agoDoes ZFS use some sort of last-used eviction to purge the cache? It seems like differentiating between random/sequential IO is a bit different than LRU.
- wmf 13y agoThe design is documented here: https://github.com/zfsonlinux/zfs/blob/master/module/zfs/arc.c#L3993 https://github.com/zfsonlinux/zfs/blob/master/module/zfs/arc...
- derefr 13y agoFor Linux specifically, there are https://github.com/mingzhao/dm-cache https://github.com/mingzhao/dm-cache and http://bcache.evilpiepirate.org/ http://bcache.evilpiepirate.org/ as well, which let you use arbitrary filesystems on top. I would bet that Linode is using one or the other of these.
- gojomo 13y agoHmm, my guess, working only from that description, would be that they've created a RAID-1 mirror with equal-sized SSD and spinning HD partitions... but are able to route reads based on the actual position of the spinning disk heads. Then, 'random' reads will usually come from the SSD, but those that happen to be under-the-head (as most often in long sequential reads) would come from the HD. I don't know if usual RAID software/controllers are already optimized for such wildly-different device response speeds (as opposed to uniform devices).
- devicenull 13y agoThis looks like something you can accomplish with md raid: http://tansi.info/hybrid/ http://tansi.info/hybrid/
- corresation 13y agoandrewcooke mentioned bcache, which is now included in the Linux kernel at of 3.10. Outside of that there are a number of storage cards and software products that offer this functionality now (essentially automatically tiered storage). For instance IBM has FlashCache, LSI has Nytro MegaRAID, and on and on.
- ghc 13y agoEvery time I think I'm done with Linode, they draw me right back in. I guess I'll wait to see about the pricing, but I imagine this will be a serious challenge for Digital Ocean to overcome, since their main selling point over Linode is cheap SSDs VPSs.
- dlau1 13y agoWaiting for digital ocean to give me some free upgrades =)
- eksith 13y agoHave you been on Digital Ocean for a while? How do you like it so far?
- xur17 13y agoI've been on Digital Ocean since the beginning of this year, and I have been very happy with it. I switched my main site over to them about 6 months ago, and haven't had any issues, and 0 (or very close to 0) downtime so far.
- nwh 13y agoI've been using them for a similar period as xur17. Have not had a single issue, bar some packet routing at AMS1 that just lead to latency for a few minutes. Their API is getting quite nice to tie into, though I've had to resort to screen scraping for some of the newer options.
- virtuz 13y agoI've been on for a while, along with RamNode. It's solid, I really like it. The interface is clean, droplets work well, they have an API, and their backups/snapshots seem to work well, too. Overall, I'm very happy, especially for the price. Would definitely recommend. Also, on a cheaper note, RamNode is amazing for the price. It's performance is _killer_ – a $28 quarterly box is running as well as one of my old client's dedicated servers from Rackspace. SSD helps with PHP a ton. Would also recommend.
- andrewcooke 13y agokind-of related, is anyone using bcache with linux yet? how easy is it to get working? does it speed things up as expected? http://arstechnica.com/information-technology/2013/07/linux-3-10-out-with-better-ssd-caching-and-radeon-support/ http://arstechnica.com/information-technology/2013/07/linux-...
- Sami_Lehtinen 13y agoWell, I've been using it for over an year now. Yes, it does really speed up things. I've found out that people grossly over estimate need for SSD space. I'm using 64 GB SSD with 3TB drive and hard disk is really rearely touched. I've even enabled power saving spin down for it, so I know when it starts. In normal daily usage HDD isn't being touched at all. It's only when something like linux updates are being run or so. I've also enabled write-back caching without maximum time limit. If you use write-through caching it naturally causes HDD to run all the time. I've chosen to cache everything, not only random reads. Because I have plenty of space with 64 GB SSD. I don't know what people are doing who claim thei need larger SSD than that. Maybe they're working with large data sets or have absolutely massive games or so. As summary, yes, I love it. SSD is never full, I'm not running out of disk space and yes, I do get pure SSD performance over 99% of the time. Only if I pickup some movies or music which has been around for months without being accessed then there's HDD access of course. Setup was ok, because I did it when I replaced my computer so I built everything from scratch anyway. I'm going to blog about that, but I have huge backlog of stuff to get blogged. P.S. Some cache vendors (like Seagate Hybrids drives) recommend using write-through caching, because in the case SSD dies, you'll still have fully working file system on HDD. With write-through caching, things are going to be very badly messed up if SSD dies. Practically totally unrecoverable situation. But that's why we got backups, right?
- chetanahuja 13y ago"With write-through caching, things are going to be very badly messed up if SSD dies" You probably meant the reverse of that (With write-back caching... etc.).
- 13y ago
- SilliMon 13y agoSounds promising. SSDs have good potential as a cache for bigger backend spinning disks.
- jcampbell1 13y agoI know there is this theory that server hardware needs to be more durable therefore you should pay an order of magnitude more, but all of my server workloads are write somewhat frequently, read randomly, and delete almost never. It is my understanding, that commodity consumer SSDs should work fine for this workload. I assume Digital Ocean is using consumer SSDs, and it feels like it shouldn't be a problem with the exception of the bad neighbor issue.
- steve-howard 13y agoActually I thought it was going the other way: "Old school" is that server hardware should be reliable so it doesn't go down, and "New school" is that hardware should be cheap and there should be a lot of it so that if one server goes down we don't care.
- jcampbell1 13y agoBoth DigitalOcean and Linode are in the "old school" camp. They are in the business of providing reliable hosting at good prices. My question was along the lines of: Using consumer HDs in servers is a disaster because the 24/7 read workload eventually breaks spinning platters. Server grade magnetic disks are a must in servers. Consumer grade SSDs are acceptable in servers because they don't wear out from 24/7 reads. Consumer SSDs fail from constant deletes+writes. Server workloads don't produce many deletes, therefore it is safe to put consumer SSDs in servers. Is the above correct? Is the premium for server grade SSDs a myth? Should I feel safe using Digital Ocean under the assumption they are using consumer SSDs for multi-tenant servers?
- patrickg_zill 13y agoAll the dedicated server providers I know, do in fact use "consumer" HDs in systems, but allow you to spend more to use "server" HDs. And, a properly equipped server for the workload being used, should not have its disks being used a lot, since loads tend to be spiky. So they should be busy during peak periods but much less busy other times.
- 13y ago
- jacques_chester 13y agoToo late. About 8 months too late.
- Kudos 13y agoToo late for... ?
- jacques_chester 13y agoFor me, at least. I run a small blogging network. Linode have upgraded RAM, added cores, added disk space. They've done everything except improve random-access I/O, which is a major bottleneck for Wordpress installations thanks to MySQL's penchant for joining tables on disk regardless of indices. I moved to DigitalOcean about 8 months ago simply to get access to SSDs. In most other respects I preferred Linode.
- apapli 13y agoHey fellow Australianite. I've been looking at using DO instead of Amazon, the main stumbling block for me is I cannot seem to figure out if they offer any configurable firewal. Ie I want to modify port rules, blocking them mostly. Does DO offer this, and how have you found them so far? My use case is similar to yours - hosting for multiple shopping carts running on MySQL, hence the appeal of SSDs.
- jacques_chester 13y agoI don't think DigitalOcean themselves offer a firewall. You'd need to block ports at your server.
- matiasb 13y agoThey don't :(
- voltagex_ 13y agoAnother Australianite here. You can just bind to localhost if you don't want things to be open to the world, or modify iptables. Your other issue in Australia is the latency to DO's servers - ~200ms for the US and 350+ for a European droplet. Cloudflare may help there, though.
- WatchDog 13y agoSounds over-engineered, slower and possibly over-priced. A consumer SSD will be faster and so long as it is trimmed correctly and not fully utilized, it should be sufficiently reliable.
- Kudos 13y agoIt's a free upgrade coming to everyone eventually.
- rektide 13y agoFor people that require a large bulk of data but who also leave most of it cold, unused, front-caching SSDs are brilliant. Paying four times as much for twice the performance and far better reliability is a no-brainer for this- what's the opposite of a bottleneck- accelerator? Data reserve+pump? What would you guess is the average interval between accesses for any given byte-on-disk a Linode customer has? If it's hours, days, or weeks, I'd call it reckless to be spending money to put those bytes on expensive SSD systems. Make the hot stuff fast, be price conscious with the rest.
- rdc12 13y agoBut your not the only person using the SSD, you can't trust that every VM, will A) Discard or B) use the SSD in a sane way.
- ing33k 13y agowhile its a welcome move, it should have been done some time ago.
- mbi 13y agoAlso worth mentioning that for 59€/mo Hetzner is offering a dedicated i7-4770 Haswell with 32GB RAM and dual SSD raid1. http://www.hetzner.de/en/hosting/produkte_rootserver/ex40ssd http://www.hetzner.de/en/hosting/produkte_rootserver/ex40ssd
- Keyframe 13y agoNB: +99€ for setup. How is everyone satisfied with hetzner? I have a few friends that run setups on their systems, mostly for heavy forums. I'm more interested how do you deal with large backups? Seems to me it's just easier to buy machines in sets for redundancy and every now and then move things over to glacier.
- mbi 13y agoHetzner includes 100GB on a SAN in a distinct datacenter with every dedicated plan (500GB is 10€, 10TB 80€.) Of course you could also push to Glacier, but that'll get counted in your outbound bandwidth (2€/TB after 20TB/mo)
- Keyframe 13y agoDo they charge for traffic between machines at hetzner?
- thejosh 13y agoIf you're OK with the latency to Europe from where you are, Hetzner is great. I used them quite a bit (and still do), however even with Cloudflare my tests were a bit sluggish here in Perth,AU.
- kulinilesh456 13y agoLindo SSDs are expensive, and the good SSDs are really, really expensive. Although the cheaper SSDs exist, they wear out more quickly, potentially slowing down as they wear, and have slower overall throughput. Not a good combination for use in multi-tenant server workloads.
- tod222 13y ago> Chicks dig scars Chicks? Really? Come on Linode, you should be better than this.
- rektide 13y agoPurify! Purify!
- orijing 13y ago> Random IO is processed first through the SSDs (the thing that they are really good at) while sequential IO short-cuts to the hard drives - which is pretty slick. Any idea why the sequential benchmark numbers improved 4-5x when it is still "short-cutting" to the HDs?
- lucian1900 13y agoPossibly because the HDDs are free to only do long sequential reads, as opposed to having to seek to some random place every now and then.
- nwmcsween 13y agoLinode has "developed" nothing. Linode is using bcache as a tiered storage but there are problems such as certain IO patterns will bypass bcache and hammer the disks causing slower-than-disk-alone IO speed.
- hosay123 13y agoFrom the description it sounds like they're just using bcache for the storage layer, or one its equivalents (IIRC Facebook came out with a very similar patch). Still pretty cool
- api 13y agoSo SSDs are bad for server loads... what secret sauce does Digital Ocean have that Linode doesn't? Did they write their own storage layer that's doing something cool?
- ksec 13y agoThings I really wish they could add or improve. PHPBB? What year is this? The Website design and structure seriously needs some thought and work. LongView, either have a trial only version of bump the free tier retention to 24 hours. What is the point of a 30 minutes graph? Get rid of the Add on, those pricing are just plain stupid. Give options to increase Memory without buying new plans for $10/GB at a maximum of double current capacity. So a $20 1GB plan could be increase to $30 2GB Memory with everything else the same $20 Plan. That should just make Linode competitive against DO. Linode CDN - A CDN coming from those 6 Linode DC with Data coming off your transfer pool. May be any Data served over CDN would count as triple the amount of data from your pool. SSD Speed up. From the Data on ServerBear, this new SSD tier is working as well as its competitors. I am sure the NodeBalancer could do with a price decrease or bump in concurrent connection. DO has all of the above in the pipeline for releasing this year, so lets hope Linode react quicker.