Mandi! Anthony D'Atri
In chel di` si favelave...
> Actually there was a firmware bug around that a while back. The HBA and
> storcli claimed to not touch drive cache, but actually were enabling it and
> lying.
Some pointer to the issue? I doubt hit me but...
Thanks.
--
ma l'impresa
Actually there was a firmware bug around that a while back. The HBA and
storcli claimed to not touch drive cache, but actually were enabling it and
lying.
> On Apr 19, 2023, at 1:41 PM, Marco Gaiarin wrote:
>
> Mandi! Mario Giammarco
> In chel di` si favelave...
>
>> The disk cache is:
Mandi! Mario Giammarco
In chel di` si favelave...
> The disk cache is:
If the controller does not lie, disk cache is disabled, see my previous
messages.
> The controller cache:
Manual say that for Non-RAID/Automatic RAID0 disks, «The only supported
cache policy for non???RAID disks is
Mandi! Konstantin Shalygin
In chel di` si favelave...
> Current controller mode is RAID. You can switch to HBA mode and disable cache
> in controller settings at the BIOS
No, is a bit complex then that.
Controller does not have an 'HBA-mode', but a 'AutoRAID0' mode.
--
Documentation is
Mandi! Matthias Ferdinand
In chel di` si favelave...
> In the first linked mail, Dan van der Ster points to this page:
> https://docs.ceph.com/en/latest/start/hardware-recommendations/#write-caches
root@pppve1:~# for d in a b c d e f; do smartctl -g wcache /dev/sd$d | grep
^Write; done
Il giorno sab 15 apr 2023 alle ore 11:10 Marco Gaiarin <
g...@lilliput.linux.it> ha scritto:
>
> Sorry, i'm a bit puzzled here.
>
> Matthias suggest to enable write cache, you suggest to disble it... or i'm
> cache-confused?! ;-)
>
>
>
> There is a cache in each disk, and a cache in the
rank Schilder
> AIT Risø Campus
> Bygning 109, rum S14
>
> ________________
> From: Konstantin Shalygin
> Sent: Saturday, April 15, 2023 11:49 AM
> To: Marco Gaiarin
> Cc: Frank Schilder; ceph-users@ceph.io
> Subject: Re: [ceph-users] Re: Some hint
_
From: Konstantin Shalygin
Sent: Saturday, April 15, 2023 11:49 AM
To: Marco Gaiarin
Cc: Frank Schilder; ceph-users@ceph.io
Subject: Re: [ceph-users] Re: Some hint for a DELL PowerEdge T440/PERC H750
Controller...
Hi,
Current controller mode is RAID. You can switch to HBA mode and
With the LSI HBAs I’ve used, HBA cache seemed to only be used for VDs, not for
passthrough drives. And then with various nasty bugs. Be careful not to
conflate HBA cache with cache on the HDD itself.
> On Apr 15, 2023, at 11:51 AM, Konstantin Shalygin wrote:
>
> Hi,
>
> Current controller
Hi,
Current controller mode is RAID. You can switch to HBA mode and disable cache
in controller settings at the BIOS
k
Sent from my iPhone
> On 15 Apr 2023, at 12:11, Marco Gaiarin wrote:
>
> Mandi! Frank Schilder
> In chel di` si favelave...
>
>>> iops: min=2, max= 40,
Mandi! Frank Schilder
In chel di` si favelave...
>> iops: min=2, max= 40, avg=21.13, stdev= 6.10, samples=929
>> iops: min=2, max= 42, avg=21.52, stdev= 6.56, samples=926
> That looks horrible.
Exactly, horrible.
The strange thing is that we came from an
>
> The truth is that:
> - hdd are too slow for ceph, the first time you need to do a rebalance or
> similar you will discover...
Depends on the needs. For cold storage, or sequential use-cases that aren't
performance-sensitive ... Can't say "too slow" without context. In Marco's
case, I
Hi,
do you want to hear the truth from real experience?
Or the myth?
The truth is that:
- hdd are too slow for ceph, the first time you need to do a rebalance or
similar you will discover...
- if you want to use hdds do a raid with your controller and use the
controller BBU cache (do not consider
> iops: min=2, max= 40, avg=21.13, stdev= 6.10, samples=929
> iops: min=2, max= 42, avg=21.52, stdev= 6.56, samples=926
That looks horrible. We also have a few SATA HDDs in Dell servers and they do
about 100-150 IOP/s read or write. Originally, I was also a bit
Mandi! Anthony D'Atri
In chel di` si favelave...
> Dell???s CLI guide describes setting individual drives in Non-RAID, which
> *smells* like passthrough, not the more-complex RAID0 workaround we had to do
> before passthrough.
>
Mandi! Matthias Ferdinand
In chel di` si favelave...
> To check current state:
> sdparm --get=WCE /dev/sdf
> /dev/sdf: SEAGATE ST2000NM0045 DS03
> WCE 0 [cha: y, def: 0, sav: 0]
> "WCE 0" means: off
> "sav: 0" means: off next time the disk is powered on
spinners are slow anyway, but on top of that SAS disks often default to
writecache=off. In use as a single disk with no risk of raid
write-holes, you can turn on writecache. On SAS, I would assume the
firmware does not lie about writes reaching stable storage (flushes).
# turn on temporarily:
How bizarre, I haven’t dealt with this specific SKU before. Some Dell / LSI
HBAs call this passthrough mode, some “personality”, some “jbod mode”, dunno
why they can’t be consistent.
> We are testing an experimental Ceph cluster with server and controller at
> subject.
>
> The controller
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