Message-ID:
 <SN4P221MB06837796CB826B7947778F1CF7182@SN4P221MB0683.NAMP221.PROD.OUTLOOK.COM>
Date: Wed, 1 May 2024 21:50:31 -0700
User-Agent: Mozilla Thunderbird
Subject: Re: Linked directory or explicit reference
To: pgsql-general@lists.postgresql.org
References: <SN4P221MB06832A96CD534D5D78BA822AF71A2@SN4P221MB0683.NAMP221.PROD.OUTLOOK.COM>
 <CANzqJaBm7ytQj7JYea+fRhfH_Hu-8LpEuqeg79XSBHuP72W-KA@mail.gmail.com>
Content-Language: en-US
From: Senor Cervesa <frio_cervesa@hotmail.com>
In-Reply-To: <CANzqJaBm7ytQj7JYea+fRhfH_Hu-8LpEuqeg79XSBHuP72W-KA@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
MIME-Version: 1.0
X-MS-Exchange-MessageSentRepresentingType: 1
X-MS-PublicTrafficType: Email
X-MS-TrafficTypeDiagnostic: SN4P221MB0683:EE_|DM8P221MB0358:EE_
X-MS-Office365-Filtering-Correlation-Id: 8c3da263-ad52-493b-82ab-08dc6a6366ba
X-Microsoft-Antispam:
	BCL:0;ARA:14566002|461199019|440099019|3412199016|3430499023;
X-Microsoft-Antispam-Message-Info:
	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
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0:
	=?utf-8?B?aENpL2ozSTNBWlpwdlgrZEhZL3VTMUJyQ1NUQ1hSUHVxN2FYejBzQXBmUDJk?=
 =?utf-8?B?c0tZQWNGREhJSDAwNlF6eTNubDV5SGZOR203RVVNZk5mTTdVYXlmQThyTjNw?=
 =?utf-8?B?dU9aL0JRVGxmb2NMUVJPd3RDbnNRbWVjUkZTTjE1K2c0ZDgvclZNYVFtR0Za?=
 =?utf-8?B?cVIydk5ENFVhVkJFby9CQ1FXYU96dkJDZkNXY250QWdzV1haelI2VWp4MGVK?=
 =?utf-8?B?YUppMC9PRnBWckF2UHEvTmdUZ3ZGbVRZRWI0RUtxWTB2ZUVCYkUxTkJLWFYr?=
 =?utf-8?B?UElYdG11OC94OHBFQnpoTDFhZmEzTFQyZGwvUU4wTC8vWW52N1FWeWY2ci9M?=
 =?utf-8?B?OW5TVlR4UjN6QW41NThZZHNzQjRaL2dBZWptNkt5K09oaElBL0hEeWJGTzhK?=
 =?utf-8?B?T0t3ZmU1OWswY2s1RDB1R3U5RVBVdXpuY2RiNzZPM1NKVnZwbzQxVHR2T2hi?=
 =?utf-8?B?ck93OXFsYm42TU5YNko1QzJtWWJyZSs5aDFuNFpKZEdweERIMEtTY2huNzdY?=
 =?utf-8?B?NTZxUTV3VGJTVU4remo1QlVOQUZBZjNmdnZDQ2QzNktqbm5QOVZSTjRqRm9Q?=
 =?utf-8?B?dGlpMDZsM2FhaTF2ZVl6cHhmNW5rQ1I1UXE2dXdWcDVWbWl6UzRNQ2ZzY3Nx?=
 =?utf-8?B?dU5abFRlNlJWN0ZjeSs4bnlGUWpMVjVqeFhySTRSYlFVeExqM1FoWnl4cHBp?=
 =?utf-8?B?VnlCU3NHa1RrMkd5aG4wR1VFZ3hQbXRZMFNyMkFBWjRXdThIa3ptOCtFQ3NY?=
 =?utf-8?B?d0pWenBxWHdscEtWYzI4MEcxaUQwdzVZK1NnSzB0d1RUYzNVK1QyTTRGK3h6?=
 =?utf-8?B?WHJ1Rnc3S3RET09uLytHMmswQzdtR0NGSCtZVmZYcDJZa215YmRnRVJQWHZM?=
 =?utf-8?B?NmVCRUR3TFA1Y2h6c1BGcXJvc2ZnSTQ2cUh3RWlpUERDdmgxSlNYRmxQZ0Qx?=
 =?utf-8?B?MXhWUXpqVDNOV0ttUEhaaE1hN2VLdUN4dDRQL1Q1VFRvWDJtVE9Rb3NHTTdQ?=
 =?utf-8?B?aXZDa29oVGVndkg0M05KMFRUUkhlM2tTZFhDa1laWk1MSEFkbEZJSGx1ZTRw?=
 =?utf-8?B?QllIT0grWVZDTUl5bHBUdHhMTnI0cVZhaC9lMWVFZE9Ra2lvYmgxbDFQL1RV?=
 =?utf-8?B?YjVkWlZyRER5aFoxcGpOYVBCYndZcGNjdDdsOG9SMm5ha2VNUDJZNFdXdFhV?=
 =?utf-8?B?c2h6V2tzTGp1eEJTb2FVL2JjakFQNW4xUjkvT04zWUlFeTVOMmhqMXBnY3NU?=
 =?utf-8?B?cW11MmJES3dSeHdkQ2pKSzFqODQwZ2NlcUZYakNZV3VHUVQvUmZCZEh1T21P?=
 =?utf-8?B?cCtGRlY1SkRJTEJaVGtxVys5YnlGUzQ4QW4veHplOE5yakxIazJydis1SkVS?=
 =?utf-8?B?eGJ4NUdmRzRqaUxKQms0NkZ0WVE4SHVvYVBDOHlQVHVjY01wbjNNdGIzWE8y?=
 =?utf-8?B?NzZIWUN6c200Ly8xYS9YYVVoQnRQKzJUTUh1dDk4bXJ2VXBvUWxhY3cxRHdN?=
 =?utf-8?B?dEZtSVU2MEs0VUpUQi9mWnU4dkUrWDlXbUpENXRIN3pYWHdGMkxRQlRkSFhz?=
 =?utf-8?B?NzdtRXJpRjNLekFNcGt3SGtQdExPS2t6d241dEdhNU91UGVsT0loRlB4QzhO?=
 =?utf-8?B?SUZ3NUs1dFpjYWFDSHM3eUVTeHM1SU1GajVhSm9rZ0JxWlBib0g2ZGxuc2F6?=
 =?utf-8?B?WFJLZzNlSm1iSzEwV3pWODVBWDdrK2MzTnBXOUlnbnFBeWx4eHlsN2MvRTNp?=
 =?utf-8?Q?vgJI5tKTaFJogVmc+4PhfQ97b5BKKpp1p43IlSi?=
X-OriginatorOrg: sct-15-20-4755-11-msonline-outlook-f5d03.templateTenant
X-MS-Exchange-CrossTenant-Network-Message-Id: 8c3da263-ad52-493b-82ab-08dc6a6366ba
X-MS-Exchange-CrossTenant-AuthSource: SN4P221MB0683.NAMP221.PROD.OUTLOOK.COM
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 May 2024 04:50:34.0533
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 84df9e7f-e9f6-40af-b435-aaaaaaaaaaaa
X-MS-Exchange-CrossTenant-RMS-PersistedConsumerOrg:
	00000000-0000-0000-0000-000000000000
X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM8P221MB0358
List-Id: <pgsql-general.lists.postgresql.org>
List-Help: <https://lists.postgresql.org/manage/>
List-Subscribe: <https://lists.postgresql.org/manage/>
List-Post: <mailto:pgsql-general@lists.postgresql.org>
List-Owner: <mailto:pgsql-general-owner@lists.postgresql.org>
List-Archive: <https://www.postgresql.org/list/pgsql-general>
Archived-At: <https://www.postgresql.org/message-id/SN4P221MB06837796CB826B7947778F1CF7182%40SN4P221MB0683.NAMP221.PROD.OUTLOOK.COM>
Precedence: bulk

On 4/30/2024 17:31, Ron Johnson wrote:
> On Tue, Apr 30, 2024 at 7:00 PM Senor Cervesa 
> <frio_cervesa@hotmail.com> wrote:
>
>     Hi All;
>
>     When doing an initial install of PostgreSQL on RHEL 7 or 8 derived
>     OS via rpm, what are pros, cons and recommendations of these 2
>     procedures for utilizing a second disk?
>
>     Secondary SSD or RAID mounted at /disk2.
>
>     Option #1
>
>      1. install the rpm which creates basic user and home
>      2. Create symlink /var/lib/pgsql/15/data --> /disk2/data
>      3. initdb with no special options
>
>     Or Option #2
>
>      1. install the rpm which creates basic user and home
>      2. initdb with --pgdata=/disk2/data
>         Probably using included 'postgresql-12-setup' script
>
>     I also link /var/lib/pgsql/data  --> ../15/data so automation can
>     reference postgresql.conf without knowing version (legacy stuff).
>
>
> In my experience,The PgBackRest restore feature does not like symlinks.
I hadn't considered that and it's the kind of experience feedback I'm 
looking for. It won't be an issue for me though.
>
>     The install is automated with a bash script which handles several
>     options including whether there is a second disk for DB. Scripting
>     the install with or without the second disk is straight forward
>     but I'm concerned with either scenario causing unforeseen differences.
>
>     I don't think there's a benefit to using tablespace here but I
>     have no experience with it. The systemd service is configured with
>     a dependency on the disk mount so I don't think there are
>     different risks for starting postgres with missing data directory.
>
>     I've run postgres in both scenarios and not had any issues. I'm
>     interested in comments from others on their experience using these
>     or other options.
>
> Is the mount point just "/disk2" when using "--pgdata=/disk2/data"?  
> I've gotten "directory not empty" errors when the mount point is 
> "/Database/x.y/data".
>
When linked, it looks like:

[root@test110 pgsql]# ll /var/lib/pgsql/15/data
lrwxrwxrwx. 1 root root 12 May  1 05:21 /var/lib/pgsql/15/data -> 
/disk2/data/

I'm not sure what would trigger "directory not empty". When running 
initdb there is nothing under data. I could see a problem with a symlink 
throwing that message as a catchall though. I haven't run across any 
problems yet.

Thank you Ron Johnson for the feedback.