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| *** | [FBI] starts logging #arpnetworks at Tue May 14 06:19:33 2019
[FBI] has joined #arpnetworks | [06:19] |
| up_the_irons | mnathani: I invited [FBI] back
LG should be back up today | [06:20] |
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| mnathani | Thank you! | [06:45] |
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| *** | ziyourenxiang has quit IRC (Ping timeout: 268 seconds) | [08:53] |
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| brycec | up_the_irons: Just curious, what kind of drives is ARP buying these days? I'm trying to shop and having a helluva time (maybe I'm just out of practice) finding *new* 4-6TB drives. I don't need more than that (a modest initial roll-out, 4 servers @ 4 drives each), under 100TB (raw) is more than enough. But... gotdamn I'm having a time. It seems the brand new drives I can find these days are 10-14TB (wow)
and they're $300+/ea (breaking the bank); anything <8TB stopped being made at least 3 years ago it seems. (I'm obviously looking at enterprice/datacenter "grade" drives, not WD Blacks or whatever) (PS I got your sales response and I'll definitely be following-up as soon as I get this initial proposal done... which is currently hung-up on sourcing fucking drives.) | [12:31] |
| mercutio | huge hard-disks are bad for VM work loads ok for archival | [12:33] |
| brycec | mercutio: precisely why I'm avoiding them too | [12:33] |
| mercutio | well 4tb is huge | [12:33] |
| brycec | You think? It was my upper limit, but it just seemed "large" not "huge" | [12:34] |
| mercutio | well most people are doing ssd these days
and not 4tb ssd :) | [12:34] |
| brycec | In any case, I'm about to start budgeting SSDs instead
lol | [12:34] |
| mercutio | you really want as many drives as you can
we have hundreds | [12:35] |
| brycec | I also feel really out of touch with buying hard drives in general. There was a time I felt comfortable buying from Amazon or Newegg, provided the seller was Amazon/Newegg and not some rando third-party that's offloading "renewed" inventory. | [12:35] |
| mercutio | 4x4 is the wrong approach.. | [12:36] |
| brycec | I get that, or at least I thought I did (quantity over capacity).
4*8? | [12:36] |
| mercutio | well you also want journal disk usually
so you want servers that can take 12+ hard-disks really | [12:36] |
| brycec | Already accounted for that, dedicated SSD for that, dedicated SSD for OS | [12:36] |
| mercutio | you want ssd per 3 or 4 disks
so like 12 disk server you may have 3 ssd and 9 data disks it's changing a bit with blue store.. | [12:36] |
| brycec | I'm limited by overall rackspace so I'm going with 2U servers, 12 slots (plus 2 for OS & journal) | [12:37] |
| mercutio | i think with bluestore it can journal rather than full copy data so you may be able to have slightly fewer ssd | [12:37] |
| brycec | Yeah I've heard Bluestore is quite improved. | [12:38] |
| mercutio | and if you're not logging shit loads then you should be able to use the same disks for journal and OS
although that does complicate things a little | [12:39] |
| brycec | Yeah I intend to do a bit of benchmarking there - RAID1 the 2 SSDs vs OS/journal split. | [12:40] |
| mercutio | with mdadm you can do raid 1 with part of the disk and not all of it
you can also do things like 3 way mirror for OS | [12:41] |
| brycec | brycec grumbles - Amazon has a limit of 20 drives/customer | [12:43] |
| mercutio | curious i wonder why that is
did you scope out what performance you need? | [12:44] |
| brycec | They probably don't trust me to not be starting my own reseller
mercutio: From my users, "better than it is now" | [12:44] |
| mercutio | damn it costs the same for 5tb and 2tb?
what iops can you do now? | [12:45] |
| brycec | I honestly couldn't say :/ | [12:45] |
| mercutio | have you tried fio?
ioping can be handy too like you can do ioping -R /dev/vda and it'll tell yuo your access times it's pretty latency dependant | [12:45] |
| brycec | Thanks I'll check those out | [12:46] |
| mercutio | fio is a little more difficult to work
but you can do things like simultaneous 4k, or 64k, or whatever requests and you can do read/write, mixed etc to a file it's basically the best tool for in depth benchmarking but you have to figure out what it is that you want to benchmark :) also for ssd for journal you want an ssd that has battery backed write cache or power loss protection as it means you get a lot lower latency... https://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test-if-your-ssd-is-suitable-as-a-journal-device/ | [12:47] |
| dne | brycec: I got 4TB HGST Ultrastar 7K6000 drives for our office bulk storage array last year - they've been fine (not using Ceph though) | [12:55] |
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| mercutio | damn they have 14tb disks now
i wonder if going for such a small cluster if it is better to just go all ssd from the get go especially when you say density is important you can get servesr that take a lot of 2.5" disks | [12:56] |
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