On 07/10/2014 12:32 PM, Pavel Odintsov wrote: > Could you share your patches to vzmigrate and vzctl?
We don't have any, where vzctl/vzmigrate didn't satisfy our needs, we've went the way around these utilities and let vpsAdmin on the hwnode manage things. You can take a look here: https://github.com/vpsfreecz/vpsadmind I wouldn't recommend anyone outside of our organization to use vpsAdmin yet, as the 2.0 transition to self-describing RESTful API is still underway. As soon as it's finished and well documented, I'll post a note here as well. The 2.0 version will be primarily controled via a CLI tool, which autogenerates itself from the API description. A running version of the API can be seen here: https://api.vpsfree.cz/v1/ Github repos: https://github.com/vpsfreecz/vpsadminapi (the API) https://github.com/vpsfreecz/vpsadminctl (the CLI tool) https://github.com/vpsfreecz/vpsadmind (deamon run on hwnode) https://github.com/vpsfreecz/vpsadmindctl (CLI tool to control the daemon) https://github.com/vpsfreecz/vpsadmin The last repo is the vpsAdmin 1.x, which all 2.0 things still require to run, it's a pain to get this running yourself, but stay tuned, once we get rid of 1.x and document 2.0 properly, it's going to be a great thing. /snajpa > > On Thu, Jul 10, 2014 at 2:25 PM, Pavel Odintsov > <[email protected]> wrote: >> Thank you for your answers! It's really useful information. >> >> On Thu, Jul 10, 2014 at 2:08 PM, Pavel Snajdr <[email protected]> wrote: >>> On 07/10/2014 11:35 AM, Pavel Odintsov wrote: >>>>> Not true, IO limits are working as they should (if we're talking vzctl >>>>> set --iolimit/--iopslimit). I've kicked the ZoL guys around to add IO >>>>> accounting support, so it is there. >>>> >>>> You can share tests with us? For standard folders like simfs this >>>> limits works bad in big number of cases >>> >>> If you can give me concrete tests to run, sure, I'm curious to see if >>> you're right - then we'd have something concrete to fix :) >>> >>>> >>>>> How? ZFS doesn't have a limit on number of files (2^48 isn't a limit >>>>> really) >>>> >>>> It's ok when your customer create 1 billion of small files on 10GB VPS >>>> and you will try to archive it for backup? On slow disk system it's >>>> really nightmare because a lot of disk operations which kills your >>>> I/O. >>> >>> zfs snapshot <dataset>@<snapname> >>> zfs send <dataset>@<snapname> > your-file or | ssh backuper zfs recv >>> <backupdataset> >>> >>> That's done on block level. No need to run rsync anymore, it's a lot >>> faster this way. >>> >>>> >>>>> Why? ZFS send/receive is able to do bit-by-bit identical copy of the FS, >>>>> I thought the point of migration is to don't have the CT notice any >>>>> change, I don't see why the inode numbers should change. >>>> >>>> Do you have really working zero downtime vzmigrate on ZFS? >>> >>> Nope, vzmigrate isn't zero downtime. Due to vzctl/vzmigrate not >>> supporting ZFS, we're implementing this our own way in vpsAdmin, which >>> in it's 2.0 re-implementation will go opensource under GPL. >>> >>>> >>>>> How exactly? I haven't seen a problem with any userspace software, other >>>>> than MySQL default setting to AIO (it fallbacks to older method), which >>>>> ZFS doesn't support (*yet*, they have it in their plans). >>>> >>>> I speaks about MySQL primarily. I have thousands of containers and I >>>> can tune MySQL for another mode for all customers, it's impossible. >>> >>> As I said, this is under development and will improve. >>> >>>> >>>>> L2ARC cache really smart >>>> >>>> Yep, fine, I knew. But can you account L2ARC cache usage per customer? >>>> OpenVZ can it via flag: >>>> sysctl -a|grep pagecache_isola >>>> ubc.pagecache_isolation = 0 >>> >>> I can't account for caches per CT, but I didn't have any need to do so. >>> >>> L2ARC != ARC, ARC is in system RAM, L2ARC is intended to be on SSD for >>> the content of ARC that is the least significant in case of low memory - >>> it gets pushed from ARC to L2ARC. >>> >>> ARC has two primary lists of cached data - most frequently used and most >>> recently used and these two lists are divided by a boundary marking >>> which data can be pushed away in low mem situation. >>> >>> It doesn't happen like with Linux VFS cache that you're copying one big >>> file and it pushes out all of the other useful data there. >>> >>> Thanks to this distinction of MRU and MFU ARC achieves far better hitrates. >>> >>>> >>>> But one customer can eat almost all L2ARC cache and displace another >>>> customers data. >>> >>> Yes, but ZFS keeps track on what's being used, so useful data can't be >>> pushed away that easily, things naturally balance themselves due to the >>> way how ARC mechanism works. >>> >>>> >>>> I'm not agains ZFS but I'm against of usage ZFS as underlying system >>>> for containers. We caught ~100 kernel bugs with simfs on EXT4 when >>>> customers do some strange thinks. >>> >>> I haven't encountered any problems especially with vzquota disabled (no >>> need for it, ZFS has its own quotas, which never need to be recalculated >>> as with vzquota). >>> >>>> >>>> But ext4 has about few thouasands developers and the fix this issues >>>> asap but ZFS on Linux has only 3-5 developers which VERY slow. >>>> Because of this I recommends using ext4 with ploop because this >>>> solution is rock stable or ZFS with ZVOL's with ext4 because this >>>> solution if more reliable and more predictable then placing ZFS >>>> containers on ZFS volumes. >>> >>> ZFS itself is a stable and mature filesystem, it first shipped as >>> production with Solaris in 2006. >>> And it's still being developed upstream as OpenZFS, that code is shared >>> between the primary version - Illumos and the ports - FreeBSD, OS X, Linux. >>> >>> So what really needs and still is being developed is the way how ZFS is >>> run under Linux kernel, but with recent release of 0.6.3, things have >>> gotten mature enough to be used in production without any fears. Of >>> course, no software is without bugs, but I can say with absolute >>> certainty that ZFS will never eat your data, the only problem you can >>> encounter is with the memory management, which is done really >>> differently in Linux than in ZFS's original habitat - Solaris. >>> >>> /snajpa >>> >>>> >>>> >>>> On Thu, Jul 10, 2014 at 1:08 PM, Pavel Snajdr <[email protected]> wrote: >>>>> On 07/10/2014 10:34 AM, Pavel Odintsov wrote: >>>>>> Hello! >>>>>> >>>>>> You scheme is fine but you can't divide I/O load with cgroup blkio >>>>>> (ioprio/iolimit/iopslimit) between different folders but between >>>>>> different ZVOL you do. >>>>> >>>>> Not true, IO limits are working as they should (if we're talking vzctl >>>>> set --iolimit/--iopslimit). I've kicked the ZoL guys around to add IO >>>>> accounting support, so it is there. >>>>> >>>>>> >>>>>> I could imagine following problems for per folder scheme: >>>>>> 1) Can't limit number of inodes in different folders (but there are >>>>>> not an inode limit for ZFS like ext4 but bug amount of files in >>>>>> container could broke node; >>>>> >>>>> How? ZFS doesn't have a limit on number of files (2^48 isn't a limit >>>>> really) >>>>> >>>>>> http://serverfault.com/questions/503658/can-you-set-inode-quotas-in-zfs) >>>>>> 2) Problems with system cache which used by all containers in HWN >>>>>> together >>>>> >>>>> This exactly isn't a problem, but a *HUGE* benefit, you'd need to see it >>>>> in practice :) Linux VFS cache is really dumb in comparison to ARC. >>>>> ARC's hitrates just can't be done with what linux currently offers. >>>>> >>>>>> 3) Problems with live migration because you _should_ change inode >>>>>> numbers on diffferent nodes >>>>> >>>>> Why? ZFS send/receive is able to do bit-by-bit identical copy of the FS, >>>>> I thought the point of migration is to don't have the CT notice any >>>>> change, I don't see why the inode numbers should change. >>>>> >>>>>> 4) ZFS behaviour with linux software in some cases is very STRANGE >>>>>> (DIRECT_IO) >>>>> >>>>> How exactly? I haven't seen a problem with any userspace software, other >>>>> than MySQL default setting to AIO (it fallbacks to older method), which >>>>> ZFS doesn't support (*yet*, they have it in their plans). >>>>> >>>>>> 5) ext4 has good support from vzctl (fsck, resize2fs) >>>>> >>>>> Yeah, but ext4 sucks big time. At least in my use-case. >>>>> >>>>> We've implemented most of vzctl create/destroy/etc. functionality in our >>>>> vpsAdmin software instead. >>>>> >>>>> Guys, can I ask you to keep your mind open instead of fighting with >>>>> pointless arguments? :) Give ZFS a try and then decide for yourselves. >>>>> >>>>> I think the community would benefit greatly if ZFS woudn't be fought as >>>>> something alien in the Linux world, which I in my experience is what >>>>> every Linux zealot I talk to about ZFS is doing. >>>>> This is just not fair. It's primarily about technology, primarily about >>>>> the best tool for the job. If we can implement something like this in >>>>> Linux but without having ties to CDDL and possibly Oracle patents, that >>>>> would be awesome, yet nobody has done such a thing yet. BTRFS is nowhere >>>>> near ZFS when it comes to running larger scale deployments and in some >>>>> regards I don't think it will ever match ZFS, just looking at the way >>>>> it's been designed. >>>>> >>>>> I'm not trying to flame here, I'm trying to open you guys to the fact, >>>>> that there really is a better alternative than you're currently seeing. >>>>> And if it has some technological drawbacks like these that you're trying >>>>> to point out, instead of pointing at them as something, which can't be >>>>> changed and thus everyone should use "your best solution(tm)", try to >>>>> think of ways how to change it for the better. >>>>> >>>>>> >>>>>> My ideas like simfs vs ploop comparison: >>>>>> http://openvz.org/images/f/f3/Ct_in_a_file.pdf >>>>> >>>>> Again, you have to see ZFS doing its magic in production under a really >>>>> heavy load, otherwise you won't understand. Any arbitrary benchmarks >>>>> I've seen show ZFS is slower than ext4, but these are not tuned for such >>>>> use cases as I'm talking about. >>>>> >>>>> /snajpa >>>>> >>>>>> >>>>>> On Thu, Jul 10, 2014 at 12:06 PM, Pavel Snajdr <[email protected]> wrote: >>>>>>> On 07/09/2014 06:58 PM, Kir Kolyshkin wrote: >>>>>>>> On 07/08/2014 11:54 PM, Pavel Snajdr wrote: >>>>>>>>> On 07/08/2014 07:52 PM, Scott Dowdle wrote: >>>>>>>>>> Greetings, >>>>>>>>>> >>>>>>>>>> ----- Original Message ----- >>>>>>>>>>> (offtopic) We can not use ZFS. Unfortunately, NAS with something >>>>>>>>>>> like >>>>>>>>>>> Nexenta is to expensive for us. >>>>>>>>>> From what I've gathered from a few presentations, ZFS on Linux >>>>>>>>>> (http://zfsonlinux.org/) is as stable but more performant than it is >>>>>>>>>> on the OpenSolaris forks... so you can build your own if you can >>>>>>>>>> spare the people to learn the best practices. >>>>>>>>>> >>>>>>>>>> I don't have a use for ZFS myself so I'm not really advocating it. >>>>>>>>>> >>>>>>>>>> TYL, >>>>>>>>>> >>>>>>>>> Hi all, >>>>>>>>> >>>>>>>>> we run tens of OpenVZ nodes (bigger boxes, 256G RAM, 12cores+, 90 CTs >>>>>>>>> at >>>>>>>>> least). We've used to run ext4+flashcache, but ext4 has proven to be a >>>>>>>>> bottleneck. That was the primary motivation behind ploop as far as I >>>>>>>>> know. >>>>>>>>> >>>>>>>>> We've switched to ZFS on Linux around the time Ploop was announced >>>>>>>>> and I >>>>>>>>> didn't have second thoughts since. ZFS really *is* in my experience >>>>>>>>> the >>>>>>>>> best filesystem there is at the moment for this kind of deployment - >>>>>>>>> especially if you use dedicated SSDs for ZIL and L2ARC, although the >>>>>>>>> latter is less important. You will know what I'm talking about when >>>>>>>>> you >>>>>>>>> try this on boxes with lots of CTs doing LAMP load - databases and >>>>>>>>> their >>>>>>>>> synchronous writes are the real problem, which ZFS with dedicated ZIL >>>>>>>>> device solves. >>>>>>>>> >>>>>>>>> Also there is the ARC caching, which is smarter then linux VFS cache - >>>>>>>>> we're able to achieve about 99% of hitrate at about 99% of the time, >>>>>>>>> even under high loads. >>>>>>>>> >>>>>>>>> Having said all that, I recommend everyone to give ZFS a chance, but >>>>>>>>> I'm >>>>>>>>> aware this is yet another out-of-mainline code and that doesn't suit >>>>>>>>> everyone that well. >>>>>>>>> >>>>>>>> >>>>>>>> Are you using per-container ZVOL or something else? >>>>>>> >>>>>>> That would mean I'd need to do another filesystem on top of ZFS, which >>>>>>> would in turn mean I'd add another unnecessary layer of indirection. ZFS >>>>>>> is a pooled storage like BTRFS is, we're giving one dataset to each >>>>>>> container. >>>>>>> >>>>>>> vzctl tries to move the VE_PRIVATE folder around, so we had to add one >>>>>>> more directory to put the VE_PRIVATE data into (see the first ls). >>>>>>> >>>>>>> Example from production: >>>>>>> >>>>>>> [[email protected]] >>>>>>> ~ # zpool status vz >>>>>>> pool: vz >>>>>>> state: ONLINE >>>>>>> scan: scrub repaired 0 in 1h24m with 0 errors on Tue Jul 8 16:22:17 >>>>>>> 2014 >>>>>>> config: >>>>>>> >>>>>>> NAME STATE READ WRITE CKSUM >>>>>>> vz ONLINE 0 0 0 >>>>>>> mirror-0 ONLINE 0 0 0 >>>>>>> sda ONLINE 0 0 0 >>>>>>> sdb ONLINE 0 0 0 >>>>>>> mirror-1 ONLINE 0 0 0 >>>>>>> sde ONLINE 0 0 0 >>>>>>> sdf ONLINE 0 0 0 >>>>>>> mirror-2 ONLINE 0 0 0 >>>>>>> sdg ONLINE 0 0 0 >>>>>>> sdh ONLINE 0 0 0 >>>>>>> logs >>>>>>> mirror-3 ONLINE 0 0 0 >>>>>>> sdc3 ONLINE 0 0 0 >>>>>>> sdd3 ONLINE 0 0 0 >>>>>>> cache >>>>>>> sdc5 ONLINE 0 0 0 >>>>>>> sdd5 ONLINE 0 0 0 >>>>>>> >>>>>>> errors: No known data errors >>>>>>> >>>>>>> [[email protected]] >>>>>>> ~ # zfs list >>>>>>> NAME USED AVAIL REFER MOUNTPOINT >>>>>>> vz 432G 2.25T 36K /vz >>>>>>> vz/private 427G 2.25T 111K /vz/private >>>>>>> vz/private/101 17.7G 42.3G 17.7G /vz/private/101 >>>>>>> <snip> >>>>>>> vz/root 104K 2.25T 104K /vz/root >>>>>>> vz/template 5.38G 2.25T 5.38G /vz/template >>>>>>> >>>>>>> [[email protected]] >>>>>>> ~ # zfs get compressratio vz/private/101 >>>>>>> NAME PROPERTY VALUE SOURCE >>>>>>> vz/private/101 compressratio 1.38x - >>>>>>> >>>>>>> [[email protected]] >>>>>>> ~ # ls /vz/private/101 >>>>>>> private >>>>>>> >>>>>>> [[email protected]] >>>>>>> ~ # ls /vz/private/101/private/ >>>>>>> aquota.group aquota.user b bin boot dev etc git home lib >>>>>>> <snip> >>>>>>> >>>>>>> [[email protected]] >>>>>>> ~ # cat /etc/vz/conf/101.conf | grep -P "PRIVATE|ROOT" >>>>>>> VE_ROOT="/vz/root/101" >>>>>>> VE_PRIVATE="/vz/private/101/private" >>>>>>> >>>>>>> >>>>>>>> _______________________________________________ >>>>>>>> Users mailing list >>>>>>>> [email protected] >>>>>>>> https://lists.openvz.org/mailman/listinfo/users >>>>>>>> >>>>>>> >>>>>>> _______________________________________________ >>>>>>> Users mailing list >>>>>>> [email protected] >>>>>>> https://lists.openvz.org/mailman/listinfo/users >>>>>> >>>>>> >>>>>> >>>>> >>>>> _______________________________________________ >>>>> Users mailing list >>>>> [email protected] >>>>> https://lists.openvz.org/mailman/listinfo/users >>>> >>>> >>>> >>> >>> _______________________________________________ >>> Users mailing list >>> [email protected] >>> https://lists.openvz.org/mailman/listinfo/users >> >> >> >> -- >> Sincerely yours, Pavel Odintsov > > > _______________________________________________ Users mailing list [email protected] https://lists.openvz.org/mailman/listinfo/users
