DataStax Enterprise has a new-ish feature set called Big Node that is supposed to help with using much denser nodes. We are going to be doing some testing with that for a similar use case with ever-growing disk needs, but no real increase in read or write volume. At some point it may become available in the open source version, too.
Sean Durity – Staff Systems Engineer, Cassandra From: Elliott Sims <elli...@backblaze.com> Sent: Thursday, April 8, 2021 6:36 PM To: user@cassandra.apache.org Subject: [EXTERNAL] Re: Huge single-node DCs (?) I'm not sure I'd suggest building a single DIY Backblaze pod. The SATA port multipliers are a pain both from a supply chain and systems management perspective. Can be worth it when you're amortizing that across a lot of servers and can exert some leverage over wholesale suppliers, but less so for a one-off. There's a lot more whitebox/OEM/etc options for high-density storage servers these days from Seagate, Dell, HP, Supermicro, etc that are worth a look. I'd agree with this (both examples) sounding like a poor fit for Cassandra. Seems like you could always just spin up a bunch of Cassandra VMs in the ESX cluster instead of one big one, but something like MySQL or PostgreSQL might suit your needs better. Or even some sort of flatfile archive with something like Parquet if it's more being kept "just in case" with no need for quick random access. For the 10PB example, it may be time to look at something like Hadoop, or maybe Ceph. On Thu, Apr 8, 2021 at 10:39 AM Bowen Song <bo...@bso.ng<mailto:bo...@bso.ng>> wrote: This is off-topic. But if your goal is to maximise storage density and also ensuring data durability and availability, this is what you should be looking at: * hardware: https://www.backblaze.com/blog/open-source-data-storage-server/ [backblaze.com]<https://urldefense.com/v3/__https:/www.backblaze.com/blog/open-source-data-storage-server/__;!!M-nmYVHPHQ!bSQzKE3v6t0ekwai3LBCp77OWeRZgl-0xUfoU3CfxwPkUCpitRxUWDlQL5dq-aP3rsu9Gco$> * architecture and software: https://www.backblaze.com/blog/vault-cloud-storage-architecture/ [backblaze.com]<https://urldefense.com/v3/__https:/www.backblaze.com/blog/vault-cloud-storage-architecture/__;!!M-nmYVHPHQ!bSQzKE3v6t0ekwai3LBCp77OWeRZgl-0xUfoU3CfxwPkUCpitRxUWDlQL5dq-aP3vxAsNFM$> On 08/04/2021 17:50, Joe Obernberger wrote: I am also curious on this question. Say your use case is to store 10PBytes of data in a new server room / data-center with new equipment, what makes the most sense? If your database is primarily write with little read, I think you'd want to maximize disk space per rack space. So you may opt for a 2u server with 24 3.5" disks at 16TBytes each for a node with 384TBytes of disk - so ~27 servers for 10PBytes. Cassandra doesn't seem to be the good choice for that configuration; the rule of thumb that I'm hearing is ~2Tbytes per node, in which case we'd need over 5000 servers. This seems really unreasonable. -Joe On 4/8/2021 9:56 AM, Lapo Luchini wrote: Hi, one project I wrote is using Cassandra to back the huge amount of data it needs (data is written only once and read very rarely, but needs to be accessible for years, so the storage needs become huge in time and I chose Cassandra mainly for its horizontal scalability regarding disk size) and a client of mine needs to install that on his hosts. Problem is, while I usually use a cluster of 6 "smallish" nodes (which can grow in time), he only has big ESX servers with huge disk space (which is already RAID-6 redundant) but wouldn't have the possibility to have 3+ nodes per DC. This is out of my usual experience with Cassandra and, as far as I read around, out of most use-cases found on the website or this mailing list, so the question is: does it make sense to use Cassandra with a big (let's talk 6TB today, up to 20TB in a few years) single-node DataCenter, and another single-node DataCenter (to act as disaster recovery)? Thanks in advance for any suggestion or comment! ________________________________ The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to our clients any opinions or advice contained in this Email are subject to the terms and conditions expressed in any applicable governing The Home Depot terms of business or client engagement letter. The Home Depot disclaims all responsibility and liability for the accuracy and content of this attachment and for any damages or losses arising from any inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other items of a destructive nature, which may be contained in this attachment and shall not be liable for direct, indirect, consequential or special damages in connection with this e-mail message or its attachment.
