7 ms·
PolarFS: Alibaba Distributed File System for Shared Storage Cloud Database [pdf]
- guilingmaster 8y agoCheck this out, interesting. https://pastebin.com/NGUVe7zi https://pastebin.com/NGUVe7zi
- RobLach 8y agoMost interesting bit is their consensus protocol.
- baotiao 8y agoThank you. We will provide our TLA+ proof soon..
- kjeetgill 8y agoI'm on mobile so I haven't been able to really fully read the paper: Can you highlight what's interesting or novel about it?
- baotiao 8y agoI think the most interesting part is PolarFS taking full advantage of the emerging techniques like RDMA, NVMe, and SPDK. And the Parallel raft consensus algorithm
- antongribok 8y agoKind of disappointing that they compared it with Ceph non-RDMA vs. PolarFS on RMDA, unless I misread this part. Still, this is all very interesting.
- sekh60 8y agoI am rather sleep deprived, so I may have misread things, but this doesn't seem to me to be the best benchmark to evaluate Ceph for database work. From what I understand best practice in ceph for databases is to make a rbd image and format that with your filesystem of choice. I believe. The rbd stripe size should be tuned to you database writes in mind. I believe ceph rbd supports rdma, but I cannot find much current details about it.
- daviesliu 8y agoThe rbd image can't be used as a shared storage for database.
- sekh60 8y agoHow not? You can map an rbd image from multiple VMs/servers at the same time, just if you want to do so you need a multi-client aware filesystem. Otherwise if you just need something attached to a single host you just format the volume ext4/xfs/whatever and map it, throw your database on that.
- j16sdiz 8y agoThe protocol is interesting. But given how often the Alibaba cloud fails in production, I won't hold my breath.
- tanilama 8y agoWill appreciate some specific examples. Disclaimer: Not Alibaba employee
- exabrial 8y agoFormer Alibaba employee: every day. There's no planning, no communication, tons of underqualified middle management, tons of politics, and a lot of really bad ideas are pushed by HIPPOs. China is general about 10-15 years behind on software development. Currently Alibaba's big push internally is a framework that essentially resembles EJB 2.1 stateful beans, but built on Spring.
- ofrzeta 8y agoI guess you are frustrated but most of it sounds like everywhere else. Also I think you are exaggerating. For sure they are not 10-15 years behind. There are some fine ideas and implementation for instance the Pouch container and p2p distribution system, even by Alibaba. Hyper.sh is chinese, too. OpenResty is nice. PingCAP, the makers of TiDB are chinese, as well.
- deleted 8y ago[deleted]
- exabrial 8y agoWell, half the time things went down is because the data center hit capacity and someone exploits something in the console to shut down your workloads, which makes for a bunch of fun.
- B1FF_PSUVM 8y ago> pushed by HIPPOs https://whatis.techtarget.com/definition/HiPPOs-highest-paid-persons-opinions https://whatis.techtarget.com/definition/HiPPOs-highest-paid...: "HiPPO (highest paid person's opinion, highest paid person in the office)"
- cbsmith 8y agoRDMA is still an "emerging technology"?
- toolslive 8y agolink is down. Is there an alternative link?
- KaiserPro 8y agoThe hardest part of a Distributed File system (and I mean File system here) is managing the Meatadata (where a file is, where the directory is, who last did something to it.) Lustre, GFS2 and GPFS all have centralised metadatstores, which is both a boon and a drawback. What I can't figure out is what they've done here. It appears like metadata is stored in a special partition ("journal") which is shared? But there is a control process as well.
- jamesblonde 8y agoIt doesn't look like PolarFS has distributed metadata. HopsFS (HDFS derivative work) stores distributed metadata, enabling 16X throughput improvements over HDFS - https://www.usenix.org/conference/fast17/technical-sessions/presentation/niazi https://www.usenix.org/conference/fast17/technical-sessions/... http://www.hops.io http://www.hops.io Technically, the hard part is correct concurrent and consistent operations across shards (partitions). Disclaimer: one of the designers of HopsFS.
- ddorian43 8y agoWhat do you think are some gotchas/limitations when using mysql-ndb-cluster ?
- jamesblonde 8y agoIt's become very stable with the years. It's somehow never penetrated the silicon valley echo chamber, probably due to instability in its earlier years. Operationally, it's got most things you need - on-line add node, rolling upgrades, monitoring, etc. We use NDB to store both the metadata in-memory, but also to store small files on NVMe disks. We had talks with lots of other DB vendors, but, frankly, none of them have high performance support for cross-partition transactions, which is needed. DBs like VoltDB, MemSQL, NuoDB all have promise, but serialize cross-shard operations.
- ryanworl 8y agoHave you explored using FoundationDB? It doesn't have a SQL interface (anymore), which might mean it isn't suitable if SQL is required.
- antoncohen 8y agoMan, reading that made me wish Clustrix (YC '06) open sourced their database (https://www.clustrix.com/ https://www.clustrix.com/). They had a MySQL compatible scale our DB nearly 10 years ago, wireline compatible with MySQL without using any MySQL code, could participate in a MySQL replication cluster with normal MySQL servers (made migration easy). It was scale out shared-nothing, writes would scale linearly as you added nodes, unlike POLARDB which is shared-everything with a single master. It used RDMA 10 years ago, and custom PCIe devices because NVMe didn't exist. But they didn't open source it, so only a small handful of companies get to use it. Sad.
- pstuart 8y agoDo you think they could have found a model to go open source and still satisfactorily monetize it?